DC power supply is usually obtained by rectification, filtering, voltage stabilization and other processes of municipal electricity. Due to the incomplete rectification or the existence of switching power supply, the output DC stability is superimposed with AC components, called ripple. The generation of ripple will bring noise, reduce the efficiency of power supply and affect the normal operation of the system. Strong ripple will cause the generation of surge voltage or current, and burn down electrical appliances and other equipment. This paper designs a detection device which can quickly and efficiently detect the ripple of carrier power supply. The experimental results show that the design system can help testers quickly judge whether the ripple of carrier module power supply meets the ripple voltage limit stipulated by Southern Power Grid Corporation, and is used to detect the ripple of power supply. Testing provides a new method of implementation.