Abstract: Soft-switching inverters have been the pupular subject in the welding power source study,and the phase-shifting zero-voltage inverted circuit is one of them.It was concluded that the conditions of realizing the zero-voltage turn-on are the enough energy stored in a welding transformer and the good watch between the control software and the circuit parameters.The comprehensive investigation on the working state and the various transfer stage of full-bridge phase-shifting inverted resistance welding machine and the analysis on the factors effecting the realization of zero-voltage turn-on were also investigated in this paper.The analyzed results were tested and verified through experiment.Moreover,although the zero-voltage turn-on can not be realized duo to some reason,the voltage stress borne by IGBT was greatly decreased and the working state of a inverted circuit was improved,applying the working way of phase-shifting inverted circuit.