Abstract: The AC leakage current generated by the non isolated AC/DC hybrid system during the normal operation is in the form of residual current, which may cause the residual current protection to malfunction and affect the electric shock fault protection effect.In this paper, from the aspects of leakage current and fault current, through the analysis of residual current characteristics, the spectrum distribution of the residual current under normal operation and accident state of the system is determined.By analyzing the human body effect of the current and the effectiveness of the RCD protection action, the residual current frequency band that affects the safety of the system is determined, and then the simulation model is used to verify the residual current characteristics of the normal system operation and electric shock accidents under the SPWM and SVPWM modulation modes, then verify the influence of distributed power access on the residual current, also the difference of residual current change in the system with single-stage and two-stage converters in the event of an accident.Finally, based on the theoretical analysis and simulation results, the protection configuration scheme of the system is proposed.