The invention discloses an auxiliary deceleration device for a train. By the auxiliary deceleration device, the brake time and distance can be effectively shortened, and the collision accidents can be prevented. The auxiliary deceleration device is characterized by consisting of a carriage (1), a choke plate slot (2), a connection piece (3), a choke plate (4), a clamping piece (5), a pull rope (6), a spring (7), and an electric lock (8); the choke plate slot (2) is a rectangular slot which is formed at each of the symmetrical positions of box bodies of two box bodies of the carriage (1); the rear side of the choke plate (4) is rotatably connected with a rear side frame of the choke plate slot (2) through the connection piece; the front of the choke plate (4) is provided with the clamping piece (5) and is connected with the choke plate slot (2) through the pull rope (6); the spring (7) is arranged in the choke plate slot (2), and the front end of the choke plate slot (2) is provided with the electric lock (8); and the end of a lock rod has an inclined surface type; and due to the whole structure, two symmetrical external opening doors are arranged on two sides of the carriage.