diff --git a/cmd/server/main.go b/cmd/server/main.go
index 958c189..12006d1 100644
--- a/cmd/server/main.go
+++ b/cmd/server/main.go
@@ -343,6 +343,7 @@ func main() {
 			authGroup.POST("/contacts/delete/:id", api.DeleteContactHandler)
 
 			// 会话管理
+			authGroup.GET("/conversations/by-room/:room_id", api.GetConversationByRoomHandler)
 			authGroup.GET("/conversations", api.GetConversationListHandler)
 			authGroup.POST("/conversations/reset-unread", api.ResetConversationUnreadHandler)
 			authGroup.POST("/conversations/update", api.UpdateConversationHandler)
diff --git a/internal/api/attachment_handler.go b/internal/api/attachment_handler.go
index 568951e..678909a 100644
--- a/internal/api/attachment_handler.go
+++ b/internal/api/attachment_handler.go
@@ -5,7 +5,9 @@
 package api
 
 import (
+	"path/filepath"
 	"strconv"
+	"strings"
 	"xk-websocket-v2/internal/model"
 	"xk-websocket-v2/internal/service"
 	"xk-websocket-v2/internal/utils"
@@ -32,17 +34,21 @@ func UploadAttachmentHandler(c *gin.Context) {
 	fileType := c.PostForm("type")
 	if fileType == "" {
 		// 根据文件扩展名推断类型
-		ext := file.Filename[len(file.Filename)-4:]
-		if ext == ".jpg" || ext == ".png" || ext == ".gif" || ext == "webp" || ext == "jpeg" {
+		ext := strings.ToLower(filepath.Ext(file.Filename))
+		if ext == ".jpg" || ext == ".jpeg" || ext == ".png" || ext == ".gif" || ext == ".webp" {
 			fileType = "image"
-		} else {
+		} else if ext == ".mp4" || ext == ".avi" || ext == ".mov" || ext == ".wmv" || ext == ".flv" || ext == ".mkv" {
 			fileType = "video"
+		} else if ext == ".mp3" || ext == ".wav" || ext == ".m4a" || ext == ".webm" || ext == ".ogg" || ext == ".aac" {
+			fileType = "audio"
+		} else {
+			fileType = "file"
 		}
 	}
 
 	// 验证文件类型
-	if fileType != "image" && fileType != "video" {
-		utils.BadRequest(c, "文件类型必须是image或video")
+	if fileType != "image" && fileType != "video" && fileType != "audio" && fileType != "file" {
+		utils.BadRequest(c, "文件类型必须是image、video、audio或file")
 		return
 	}
 
@@ -55,6 +61,14 @@ func UploadAttachmentHandler(c *gin.Context) {
 		utils.BadRequest(c, "视频大小不能超过500MB")
 		return
 	}
+	if fileType == "audio" && file.Size > model.MaxAudioSize {
+		utils.BadRequest(c, "音频大小不能超过50MB")
+		return
+	}
+	if fileType == "file" && file.Size > model.MaxFileSize {
+		utils.BadRequest(c, "文件大小不能超过100MB")
+		return
+	}
 
 	// 打开文件
 	src, err := file.Open()
diff --git a/internal/api/conversation_handler.go b/internal/api/conversation_handler.go
index 9d4175b..cce4e27 100644
--- a/internal/api/conversation_handler.go
+++ b/internal/api/conversation_handler.go
@@ -9,6 +9,7 @@ import (
 	"xk-websocket-v2/internal/utils"
 
 	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
 )
 
 /**
@@ -119,4 +120,30 @@ func DeleteConversationHandler(c *gin.Context) {
 	utils.Success(c, "删除成功")
 }
 
+/**
+ * GetConversationByRoomHandler
+ * 功能：根据 room_id 获取或创建会话
+ * 路径：GET /api/conversations/by-room/:room_id
+ */
+func GetConversationByRoomHandler(c *gin.Context) {
+	userID, _ := c.Get("user_id")
+	roomID := c.Param("room_id")
+
+	if roomID == "" {
+		utils.BadRequest(c, "room_id 不能为空")
+		return
+	}
+
+	conv, err := service.ConversationSvc.GetOrCreateConversationByRoom(userID.(string), roomID)
+	if err != nil {
+		if err == gorm.ErrRecordNotFound {
+			utils.NotFound(c, "房间不存在或无权访问")
+		} else {
+			utils.InternalError(c, "查询失败")
+		}
+		return
+	}
+
+	utils.SuccessWithData(c, conv, "获取成功")
+}
 
diff --git a/internal/model/types.go b/internal/model/types.go
index c3cbfd1..50da703 100644
--- a/internal/model/types.go
+++ b/internal/model/types.go
@@ -581,8 +581,10 @@ const (
 	ChanClusterBroadcast = "ws:cluster:broadcast"
 
 	// 文件大小限制（字节）
-	MaxImageSize = 10 * 1024 * 1024  // 10MB
-	MaxVideoSize = 500 * 1024 * 1024 // 500MB
+	MaxImageSize = 10 * 1024 * 1024   // 10MB
+	MaxVideoSize = 500 * 1024 * 1024  // 500MB
+	MaxAudioSize = 50 * 1024 * 1024   // 50MB
+	MaxFileSize  = 100 * 1024 * 1024  // 100MB
 
 	// 消息类型常量
 	MessageTypeText        = 0 // 文本
diff --git a/internal/service/attachment_service.go b/internal/service/attachment_service.go
index a209e24..15e2ea0 100644
--- a/internal/service/attachment_service.go
+++ b/internal/service/attachment_service.go
@@ -35,6 +35,8 @@ func InitAttachmentService(db *gorm.DB) {
 	// 创建上传目录
 	os.MkdirAll("./uploads/images", os.ModePerm)
 	os.MkdirAll("./uploads/videos", os.ModePerm)
+	os.MkdirAll("./uploads/audio", os.ModePerm)
+	os.MkdirAll("./uploads/files", os.ModePerm)
 }
 
 /**
@@ -49,8 +51,8 @@ func InitAttachmentService(db *gorm.DB) {
  */
 func (s *AttachmentService) UploadFile(userID, fileName, fileType string, fileSize int64, fileData io.Reader) (*model.Attachment, error) {
 	// 验证文件类型
-	if fileType != "image" && fileType != "video" {
-		return nil, errors.New("文件类型必须是image或video")
+	if fileType != "image" && fileType != "video" && fileType != "audio" && fileType != "file" {
+		return nil, errors.New("文件类型必须是image、video、audio或file")
 	}
 
 	// 验证文件大小
@@ -60,12 +62,22 @@ func (s *AttachmentService) UploadFile(userID, fileName, fileType string, fileSi
 	if fileType == "video" && fileSize > model.MaxVideoSize {
 		return nil, fmt.Errorf("视频大小不能超过%dMB", model.MaxVideoSize/(1024*1024))
 	}
+	if fileType == "audio" && fileSize > model.MaxAudioSize {
+		return nil, fmt.Errorf("音频大小不能超过%dMB", model.MaxAudioSize/(1024*1024))
+	}
+	if fileType == "file" && fileSize > model.MaxFileSize {
+		return nil, fmt.Errorf("文件大小不能超过%dMB", model.MaxFileSize/(1024*1024))
+	}
 
-	// 验证文件扩展名
+	// 获取文件扩展名
 	ext := strings.ToLower(filepath.Ext(fileName))
-	allowedExts := s.getAllowedExtensions(fileType)
-	if !contains(allowedExts, ext) {
-		return nil, fmt.Errorf("不支持的文件类型，允许的类型: %v", allowedExts)
+	
+	// 验证文件扩展名（file类型不限制扩展名）
+	if fileType != "file" {
+		allowedExts := s.getAllowedExtensions(fileType)
+		if len(allowedExts) > 0 && !contains(allowedExts, ext) {
+			return nil, fmt.Errorf("不支持的文件类型，允许的类型: %v", allowedExts)
+		}
 	}
 
 	// 生成唯一文件名
@@ -75,10 +87,17 @@ func (s *AttachmentService) UploadFile(userID, fileName, fileType string, fileSi
 
 	// 确定保存路径
 	var saveDir string
-	if fileType == "image" {
+	switch fileType {
+	case "image":
 		saveDir = "./uploads/images"
-	} else {
+	case "video":
 		saveDir = "./uploads/videos"
+	case "audio":
+		saveDir = "./uploads/audio"
+	case "file":
+		saveDir = "./uploads/files"
+	default:
+		saveDir = "./uploads/files"
 	}
 
 	filePath := filepath.Join(saveDir, newFileName)
@@ -97,7 +116,20 @@ func (s *AttachmentService) UploadFile(userID, fileName, fileType string, fileSi
 	}
 
 	// 生成访问URL
-	fileURL := fmt.Sprintf("/uploads/%s/%s", fileType+"s", newFileName)
+	var urlPrefix string
+	switch fileType {
+	case "image":
+		urlPrefix = "images"
+	case "video":
+		urlPrefix = "videos"
+	case "audio":
+		urlPrefix = "audio"
+	case "file":
+		urlPrefix = "files"
+	default:
+		urlPrefix = "files"
+	}
+	fileURL := fmt.Sprintf("/uploads/%s/%s", urlPrefix, newFileName)
 
 	// 获取MIME类型
 	mimeType := mime.TypeByExtension(ext)
@@ -189,10 +221,19 @@ func (s *AttachmentService) GetUserAttachments(userID, fileType string, page, pa
 
 // 辅助函数：获取允许的文件扩展名
 func (s *AttachmentService) getAllowedExtensions(fileType string) []string {
-	if fileType == "image" {
+	switch fileType {
+	case "image":
 		return []string{".jpg", ".jpeg", ".png", ".gif", ".webp"}
+	case "video":
+		return []string{".mp4", ".avi", ".mov", ".wmv", ".flv", ".mkv"}
+	case "audio":
+		return []string{".mp3", ".wav", ".m4a", ".webm", ".ogg", ".aac", ".flac"}
+	case "file":
+		// 文件类型允许所有扩展名，但排除图片、视频、音频的扩展名
+		return []string{} // 空数组表示不限制扩展名
+	default:
+		return []string{}
 	}
-	return []string{".mp4", ".avi", ".mov", ".wmv", ".flv", ".mkv"}
 }
 
 // 辅助函数：检查字符串是否在切片中
diff --git a/internal/service/conversation_service.go b/internal/service/conversation_service.go
index d3b70cc..c81af01 100644
--- a/internal/service/conversation_service.go
+++ b/internal/service/conversation_service.go
@@ -50,6 +50,9 @@ func (s *ConversationService) GetConversations(userID string) ([]model.ChatConve
 			var room model.ChatRoom
 			if err := s.DB.Where("room_id = ?", list[i].RoomID).First(&room).Error; err == nil {
 				list[i].Room = &room
+			} else {
+				// 记录警告：群聊信息查询失败
+				log.Printf("⚠️ 群聊信息查询失败 (room_id: %s): %v", list[i].RoomID, err)
 			}
 		}
 	}
@@ -257,4 +260,118 @@ func buildMessageSummary(msg model.ChatMessage, isGroupChat bool, senderUserID s
 	return content
 }
 
+/**
+ * GetOrCreateConversationByRoom
+ * 功能：根据 room_id 获取或创建会话
+ * @param userID 用户ID
+ * @param roomID 房间ID
+ * @returns 会话对象和错误
+ */
+func (s *ConversationService) GetOrCreateConversationByRoom(userID, roomID string) (*model.ChatConversation, error) {
+	if s == nil {
+		return nil, gorm.ErrRecordNotFound
+	}
+
+	// 查询房间信息以确定类型
+	var room model.ChatRoom
+	roomErr := s.DB.Where("room_id = ?", roomID).First(&room).Error
+	
+	var conversationType int
+	var targetID string
+	
+	if roomErr == nil {
+		// 房间存在，根据房间类型判断
+		if room.RoomType == "group" {
+			conversationType = 2 // 群聊
+			targetID = roomID    // 群聊时 targetID = roomID
+		} else {
+			conversationType = 1 // 私聊
+			// 私聊需要确定 targetID（对方用户ID）
+			// 从 room_members 中查找另一个成员
+			var members []model.RoomMember
+			if err := s.DB.Where("room_id = ?", roomID).Find(&members).Error; err == nil {
+				for _, member := range members {
+					if member.UserID != userID {
+						targetID = member.UserID
+						break
+					}
+				}
+			}
+			if targetID == "" {
+				return nil, gorm.ErrRecordNotFound
+			}
+		}
+	} else {
+		// 房间不存在，尝试通过 roomID 格式判断
+		if len(roomID) > 6 && roomID[:6] == "group_" {
+			conversationType = 2 // 群聊
+			targetID = roomID
+		} else {
+			// 可能是私聊，尝试从 room_members 查找
+			var members []model.RoomMember
+			if err := s.DB.Where("room_id = ?", roomID).Find(&members).Error; err == nil && len(members) == 2 {
+				conversationType = 1 // 私聊
+				for _, member := range members {
+					if member.UserID != userID {
+						targetID = member.UserID
+						break
+					}
+				}
+			} else {
+				return nil, gorm.ErrRecordNotFound
+			}
+		}
+	}
+
+	// 查询会话
+	var conv model.ChatConversation
+	tx := s.DB.Where("user_id = ? AND target_id = ? AND type = ?", userID, targetID, conversationType).First(&conv)
+	
+	if tx.Error != nil {
+		if tx.Error == gorm.ErrRecordNotFound {
+			// 创建新会话
+			conv = model.ChatConversation{
+				UserID:      userID,
+				TargetID:    targetID,
+				RoomID:      roomID,
+				Type:        conversationType,
+				LastMessage: "",
+				LastTime:    time.Now(),
+				UnreadCount: 0,
+			}
+			if err := s.DB.Create(&conv).Error; err != nil {
+				return nil, err
+			}
+		} else {
+			return nil, tx.Error
+		}
+	}
+
+	// 加载关联信息
+	if conv.Type == 1 { // 私聊：加载目标用户信息
+		var user model.User
+		if err := s.DB.Where("id = ?", conv.TargetID).First(&user).Error; err == nil {
+			conv.TargetUser = &user
+		} else {
+			log.Printf("⚠️ 用户信息查询失败 (user_id: %s): %v", conv.TargetID, err)
+		}
+	} else if conv.Type == 2 { // 群聊：加载群信息
+		if roomErr == nil {
+			// 之前查询成功，直接使用
+			conv.Room = &room
+		} else {
+			// 如果之前查询失败，再次尝试查询
+			var retryRoom model.ChatRoom
+			if err := s.DB.Where("room_id = ?", roomID).First(&retryRoom).Error; err == nil {
+				conv.Room = &retryRoom
+			} else {
+				log.Printf("⚠️ 群聊信息查询失败 (room_id: %s): %v", roomID, err)
+				// 即使查询失败，也返回会话，但 Room 字段为 nil
+			}
+		}
+	}
+
+	return &conv, nil
+}
+