The invention discloses a detection system and method for preventing collisions of track cars. The system comprises a plurality of anti-collision devices arranged at the front end of a later track car side by side, a processor, a reflection mirror face and a control system. The processor is arranged on the later track car and used for calculating the distance between a front track car and the later track car according to diffusion signals, the reflection mirror face is arranged at the rear end of the front track car and used for reflecting the diffusion signals, and the control system is connected with the processor and used for controlling the speed of the later track car according to the calculated distance.