The invention discloses a rail traffic shielding door transmission device which comprises a door machine beam, a transmission belt device and shielding door hangers. The transmission belt device comprises a driving wheel, a driven wheel, a transmission belt and a drive device, the drive device is connected with the driving wheel through a drive shaft, the driving wheel and the driven wheel are vertically and fixedly arranged in the door machine beam, guide plates and limit plates are arranged on the upper end surface and the lower end surface of the driving wheel, the guide plates extend outwards along the contour line of the transmission belt, sliding guide grooves are formed in the guide plates, a plurality of freely sliding connectors are mounted in the skidding guide grooves and connected with the transmission belt. The shielding door is of a double-door hinged type, the first shielding door is arranged on the transmission belt of one side close to a front platform through the shielding door hangers, and the second shielding door is arranged on the transmission belt of one side far away from the front platform through the shielding door hangers. According to the transmission device, number of the driving device is decreased, a transmission structure is simple, transition movements are less, and reliability of the device is improved.