The electric life of AC contactor is affected by many factors, among which the coil control mode is one of the main factors. Coil current zero-crossing breaking mode is one of the commonly used for AC contactor coil drive circuit, and its working characteristics affect the electrical life of AC contactor. In this paper, firstly, the operating characteristics of ac contactor under this control mode are analyzed, which lead to unbalance erosion loss in three-phase contact and among which one of contacts is most serious erosion all the time. Secondly, the distribution uniformity of first quenching phase is put forward to judge the maximum erosion phase, and the residual life prediction model was established based on the theory that the maximum wear phase is the first failure phase. Finally, the electrical life test of AC contactor is conducted under in the control mode of SSR, and test data analysis shows that this model can realize residual electric life prediction of AC contactor.