The performance of arc welding power source is an important factor that affecting the use safe and welding quality, so a special equipment for the factory testing is required. The test equipment for arc welding power supply is master-slave structure, and includes hardware and software system. Hardware system complete data acquisition and information display, controlled by embedded micro-controller. The software system complete a graphical user interface programs and collection procedures, developed in the embedded Linux environment. The device enables the automated testing of the welding power source, such as loading, data transmission, reflecting a good man-machine interactivity. The system will be applied to the factory inspection of welding power source, to assess its the quality and performance through tested parameters.