Abstract: A CO₂ inverter welding system with waveform control is established,in which the Intel 19-bit microprocessor 80C196KC is adopted as the central controller.The structure of the system is introduced,then the working principle of the subsystems are given in detail,such as the main circuit,driving circuit,mini-system of microprocessor,setting and display system of the welding parameters,and the wire feeding system together with the welding sequence control circuit.The output characteristic is controlled using a double-close-loop method,which is fulfilled by software,The principle of this controlling method and the output waveform are given.In the experiments followed,various output waveforms are applied to meet the special requirements for different welding conditions.The results show that besides its simple structure and easy operation,the system has good controlling performance.