Abstract: This paper briefly introduced the characteristic and function of Proteus software, and then described the approach of its application in the development of embedded digital control system for welding and cutting.An AT89S51 MCU based control system, which was developed for inverter-type air plasma cutting machine, was designed, programmed, simulated and debugged by using Proteus and Keil C.Results verify that it is possible to test the system accurately and the system has expected functions.This method is proved to be an effective means which raises the development efficiency, reduces the cycle time and saves costs.