diff --git a/include/record_manager.hpp b/include/record_manager.hpp
index ec7c414..8ad8ee6 100644
--- a/include/record_manager.hpp
+++ b/include/record_manager.hpp
@@ -57,6 +57,7 @@ class RecordManager
 
     // === 文件列表索引 ===
     std::unordered_map<std::string, std::vector<RecordFileInfo>> index_;
+    std::mutex index_mutex_;
 
     // 解析文件名得到 start_ms 和 end_ms
     RecordFileInfo parseFile(const std::filesystem::path& p);
diff --git a/src/record_manager.cpp b/src/record_manager.cpp
index 8ae8eda..ffbbb32 100644
--- a/src/record_manager.cpp
+++ b/src/record_manager.cpp
@@ -164,6 +164,8 @@ void RecordManager::stopAutoScan()
 //
 void RecordManager::scanAll()
 {
+    std::lock_guard<std::mutex> lock(index_mutex_);
+
     index_.clear();
 
     if (!fs::exists(record_dir_))
@@ -261,6 +263,8 @@ RecordFileInfo RecordManager::parseFile(const fs::path& p)
 //
 std::vector<RecordSegment> RecordManager::querySegments(const std::string& stream, int64_t start_ms, int64_t end_ms)
 {
+    std::lock_guard<std::mutex> lock(index_mutex_);
+
     std::vector<RecordSegment> result;
     if (start_ms <= 0 || end_ms <= 0 || start_ms >= end_ms) return result;
     if (!index_.count(stream)) return result;
@@ -322,6 +326,8 @@ std::vector<RecordSegment> RecordManager::querySegments(const std::string& strea
 //
 RecordSegment RecordManager::getSegment(const std::string& segmentId)
 {
+    std::lock_guard<std::mutex> lock(index_mutex_);
+
     // 1) 找最后一个 "_"
     size_t pos_last = segmentId.rfind('_');
     if (pos_last == std::string::npos) return {};