Abstract: The synergic pulsed MIG welding has been expanded rapidly because of its advantages of no spatter,stabilized process and easy operation.But it lacks adaptability ard flexibility,and its circuit is complicated.A pulsed MIG welding system of microcomputer control has been developed.The system not only can do synergic control but also can compensate the changes of the unified coordinate relationship caused by the change of the nozzle height.It ensures a transfer of one droplet in one pulse.The principle of control and the compensation method are introduced in the paper,too.The test results showed that the system has stronger compensation capability against the change cf nozzle height,as well as the advantages of general synergic control.Hard-ware circuit has been simplified.The adaptability and flexibility of the power source are improved.