diff --git a/perception/lidar_apollo_instance_segmentation/launch/lidar_apollo_instance_segmentation.launch.xml b/perception/lidar_apollo_instance_segmentation/launch/lidar_apollo_instance_segmentation.launch.xml
index 9fed29828ed9f..78127590685fb 100644
--- a/perception/lidar_apollo_instance_segmentation/launch/lidar_apollo_instance_segmentation.launch.xml
+++ b/perception/lidar_apollo_instance_segmentation/launch/lidar_apollo_instance_segmentation.launch.xml
@@ -13,7 +13,7 @@
   <arg name="param_file" default="$(find-pkg-share lidar_apollo_instance_segmentation)/config/$(var base_name).param.yaml"/>
 
   <arg name="target_frame" default="base_link"/>
-  <arg name="z_offset" default="-2"/>
+  <arg name="z_offset" default="-2.0"/>
 
   <node pkg="lidar_apollo_instance_segmentation" exec="lidar_apollo_instance_segmentation_node" name="lidar_apollo_instance_segmentation" output="screen">
     <remap from="input/pointcloud" to="$(var input/pointcloud)"/>
diff --git a/perception/lidar_apollo_instance_segmentation/src/detector.cpp b/perception/lidar_apollo_instance_segmentation/src/detector.cpp
index af8b29f55f340..77eee2c551846 100644
--- a/perception/lidar_apollo_instance_segmentation/src/detector.cpp
+++ b/perception/lidar_apollo_instance_segmentation/src/detector.cpp
@@ -38,7 +38,7 @@ LidarApolloInstanceSegmentation::LidarApolloInstanceSegmentation(rclcpp::Node *
   use_intensity_feature = node_->declare_parameter("use_intensity_feature", true);
   use_constant_feature = node_->declare_parameter("use_constant_feature", true);
   target_frame_ = node_->declare_parameter("target_frame", "base_link");
-  z_offset_ = node_->declare_parameter("z_offset", 2);
+  z_offset_ = node_->declare_parameter<float>("z_offset", -2.0);
 
   // load weight file
   std::ifstream fs(engine_file);