The testing of security and stability control devices is a key problem for both manufacturers and customers. This paper analyzes the functional requirements of a universal tester， introduces its overall structure， software and hardware characteristics. This paper also explains the universal design characteristics to adapt to different types of security and stability control devices. It then quotes the testing report and analyzes the output accuracy of the tester. Moreover， this paper describes in detail the analog waveform reproduction of the relevant hardware and software methods and the formula. The formula are capable of capturing the standard sine wave as well as reflecting all sorts of failure waveforms.