Human body pose estimation has a wide range of applications in the field of artificial intelligence and is gradually applied in daily life. However, for some specific scenes and people, privacy and security need to be ensured, and devices such as cameras are no longer the optimal choice, so this paper proposes the idea of using LiDAR technology to acquire human body point cloud images, and preprocessing and segmentation to extract a pure human body point cloud model. First, the useful parts around the human body are extracted by preprocessing the point cloud image obtained from LiDAR scanning. Then, a segmentation technique is utilized to separate the human body from the surrounding objects, keeping only the human body part. Next, the excess noise is removed by filtering process to get the pure human body point cloud model. Finally, the motionBert3d model is used to estimate the pose of the preprocessed point cloud image, and the pose estimation points and the 3D pose estimation model of the human body are obtained, which lays the foundation for the subsequent human motion recognition.