Abstract: Mo alloyed layer on the surface of TiNi alloy substrate was obtained by using the double glow plasma surface alloying technique, and phase and composition distribution of the Mo alloyed layer were investigated. The electrochemical performance and wear resistance of Mo alloyed layer and TiNi alloy substrate samples were studied by by ultrasonic vibration cavitation erosion test machine with electrochemical measurement system and the reciprocating friction and wear tester. The results show that the atomic concentration of Mo alloyed layer presented gradient distribution and Mo alloyed layer was mainly composed of Mo, MoTi and Ni₃Ti phases. The passivation capability of the substrate was suppressed during the cavitation, while Mo alloyed sample showed the passivation in a certain extent. The wear mechanism of Mo alloyed sample and the substrate alloy sample were abrasive wear and adhesive wear. The wear scar width of TiNi alloy substrate was much larger than that of Mo alloyed sample, and the adhesive wear of the substrate alloy was more serious.