Designed the main circuit of inverter welder with a FB-ZVS-PWM full-bridge IGBT inverter work as inverter main circuit topology, which consisted of the input rectifier filter circuit, inverter and output rectifier circuit. Analyzed the main circuit working principle and designed parameters of the components. Based on it, made the MATLAB simulation, and set up a prototype on the theoretical basis and made an experiment. The simulation result and prototype experimental result both demonstrated rationality and feasibility of the proposed circuit design.