With the rapid development of high-speed railway and rail transit, how to realize the safety of passengers between the platform and the train is urgent. At present, the protection system adopted has the potential of missing detection, poor reliability of artificial detection and weak anti-interference ability of the system. Lidar can have the advantages of omni-directional scanning, high reliability, simple installation and maintenance, and find the target in the protection area Alarm in real time to prevent accidental injury.