diff --git a/cmvr-es/simulate/mujoco/mujoco_viewer/include/mujoco_viewer.h b/cmvr-es/simulate/mujoco/mujoco_viewer/include/mujoco_viewer.h
index 9af82f7a..74a18731 100644
--- a/cmvr-es/simulate/mujoco/mujoco_viewer/include/mujoco_viewer.h
+++ b/cmvr-es/simulate/mujoco/mujoco_viewer/include/mujoco_viewer.h
@@ -109,6 +109,8 @@ namespace cmvr {
         mjvScene pip_scene_;
         bool pip_scene_inited_ = false;
         mjModel *pip_scene_model_ = nullptr;
+        mjData *pip_render_data_ = nullptr;
+        mjModel *pip_render_data_model_ = nullptr;
         mutable std::mutex pip_rgb_mtx_;
         std::vector<unsigned char> pip_rgb_;
         std::vector<float> pip_depth_;     // 新增：z-buffer
diff --git a/cmvr-es/simulate/mujoco/mujoco_viewer/src/mujoco_viewer.cpp b/cmvr-es/simulate/mujoco/mujoco_viewer/src/mujoco_viewer.cpp
index 300456dd..a5d84cd5 100644
--- a/cmvr-es/simulate/mujoco/mujoco_viewer/src/mujoco_viewer.cpp
+++ b/cmvr-es/simulate/mujoco/mujoco_viewer/src/mujoco_viewer.cpp
@@ -76,6 +76,11 @@ namespace cmvr {
             mjv_freeScene(&pip_scene_);
             pip_scene_inited_ = false;
         }
+        if (pip_render_data_ != nullptr) {
+            mj_deleteData(pip_render_data_);
+            pip_render_data_ = nullptr;
+            pip_render_data_model_ = nullptr;
+        }
     }
 
     mjModel* MuJocoViewer::model() const {
@@ -207,7 +212,33 @@ namespace cmvr {
         display_rect.left = left;
         display_rect.bottom = bottom;
 
-        const std::unique_lock<std::recursive_mutex> lock(sim_->mtx);
+        // Copy only the visualization state while synchronized with Simulate.
+        // Keep scene update, GPU rendering and pixel readback out of this lock
+        // so the world sync thread cannot hold the simulation mutex while
+        // waiting for the viewer.
+        {
+            std::unique_lock<std::recursive_mutex> lock(sim_->mtx, std::try_to_lock);
+            if (lock.owns_lock()) {
+                if (pip_render_data_model_ != render_model) {
+                    if (pip_render_data_ != nullptr) {
+                        mj_deleteData(pip_render_data_);
+                        pip_render_data_ = nullptr;
+                    }
+                    pip_render_data_ = mj_makeData(render_model);
+                    pip_render_data_model_ = render_model;
+                }
+                if (pip_render_data_ != nullptr) {
+                    mjv_copyData(pip_render_data_, render_model, render_data);
+                }
+            }
+        }
+
+        // The simulation lock is intentionally non-blocking.  If the sync
+        // thread owns it, use the last complete snapshot so every back buffer
+        // still gets the PiP overlay; skip only until the first snapshot exists.
+        if (pip_render_data_ == nullptr || pip_render_data_model_ != render_model) {
+            return;
+        }
 
         if (!pip_scene_inited_ || pip_scene_model_ != render_model) {
             if (pip_scene_inited_) {
@@ -222,7 +253,7 @@ namespace cmvr {
         pip_cam_.fixedcamid = pip_camera_id_;
         pip_cam_.trackbodyid = -1;
 
-        mjv_updateScene(render_model, render_data, &opt_, &pert_, &pip_cam_, mjCAT_ALL, &pip_scene_);
+        mjv_updateScene(render_model, pip_render_data_, &opt_, &pert_, &pip_cam_, mjCAT_ALL, &pip_scene_);
 
         auto& context = sim_->platform_ui->mjr_context();
         const int offscreen_width = context.offWidth > 0 ? context.offWidth : display_rect.width;