A welding system based on a push- pull wire feeder was designed and how it works was analyzed. The system included the welding power supply, the wire feeding system, and the coordination controller. The power supply used a current mode PWM IC UC3846 as the controller, which made sure the security and the dynamitic responsibility of the system. The critical fact to realize the push-pull wire feeding system was that a small inertia and fast response AC servo motor was selected. TMS320F2808 was used as the core coordination controller of the system, which made the welding power source and the wire feeding system work coordinately. The motor will pull the wire back when the arc was in the period of short-circuiting, and push the wire forward when the arc was in arc period. The results proved the system can meet the welding demands.