The invention discloses a sliding pedal device for a rail transit train. The sliding pedal device comprises a mounting chassis, a driving motor, a driving assembly, a lock body assembly, a guiding assembly, a pedal assembly, installing blocks and a bearing wheel assembly. When the driving motor works normally, a pushing plate is controlled to perform linear motion by the driving assembly and drives a guiding column to perform linear motion, and accordingly automatic control of linear sliding of the pedal assembly along the bearing wheel assembly is achieved. When the lock body assembly is operated to unlock a driving motor brake, the pushing plate is manually pulled to perform linear motion and drives the guiding column to perform linear motion, and accordingly manual control of linear sliding of the pedal assembly along the bearing wheel assembly is achieved. After the pedal assembly is put away in place, the pedal assembly is isolated through the lock body assembly to achieve pedal isolation. The sliding pedal device avoids potential safety hazards occurred when passengers tread into gaps, adopts electric, manual and isolating states, has a misoperation preventing function, improves the safety of the pedal assembly and has a good application prospect.