A collision brake deceleration system used for a single-line railroad entertainment vehicle comprises a collision buffering device and an assistant brake deceleration device. The assistant brake deceleration device comprises a brake cable line, one end of the brake cable line is connected with a brake on a rear wheel of the vehicle, and the other end of the brake cable line is connected with the collision buffering device. The collision brake deceleration system used for the single-line railroad entertainment vehicle has the advantages that the structure is simple, the manufacturing cost is low, the response is flexible, and impact to the whole vehicle and a driver is small; when the vehicle deviates from a track severely, the vehicle deceleration is not operated by the driver but achieved by converting part of kinetic energy of the vehicle into energy of other forms and triggering the brake after the vehicle makes contact with the track and collides with the track.