The driver controller of the subway train is the core control equipment of the vehicle and is the main command appliance for subway train traction and control. Aiming at the problem that the existing driver controller has a complex structure and low digitalization level and cannot interact with the data of metro train control and diagnostic system, a digital driver controller design scheme based on STM32 is proposed and a prototype is developed. The new design adopts two 9-channel encoders to detect the position of traction handle and 12 opt isolators to detect the switching status of driver controller IO nodes, and the measured handle position information and node status information are mutually corroborated to satisfy the error to be valid; meanwhile, a 2-way industrial Ethernet interface is designed to comply with TRDP communication protocol, which can output the driver controller status in real-time. Finally, in order to verify the feasibility of the system was carried out type test, network consistency test and actual loading debugging, the results show that the designed digital driver controller is compact, highly reliable, functional and basically meets the needs of the actual loading. The design improves the digital level of the subway train driver controller, enables self-diagnosis and recording of many types of faults, and improves system reliability.