Abstract: In view of the piezoelectric technology application in rail detection, which is limited by testing speed, acoustic coupling and the complicated structure, a rail defects detecting equipment based on electromagnectic acoustic technique has been investigated. The multi-channel transmitting and receiving circuits were designed in order to achieve the comprehensive tests. The mechanical structure was designed which effectively solved the loose structure and interference problem. The way to achieve high power transmitting and low noise receiving was designed. The self-correlation method was designed, which was applied in the rail flaw detection system. Experiments showed that the equipment could detect the rail flaws efficiently and indicated that the device had advantages of being independent of couplant and simple structure.