Abstract: In response to the demand for the perception and warning of "low slow small" Unmanned Aerial Vehicle (UAV) along the railway, this paper designed a railway "low slow small" UAV situational awareness and warning platform, and elaborated on the overall architecture, network architecture, specific functions, and key technologies of the platform. The platform has been put into trial operation in the pilot area of China Railway Beijing Group Co. Ltd., which can assist the railway department in monitoring and early warning of "low slow small" UAV, reduce the probability that "low slow small" UAV pose a threat to railway operation safety, and provide effective technical support for railway safety production.