Based on a new type of USB bus interface chip CH372, a human interface devices-USB mouse is designed. The working principle and characteristics of CH372 are expounded, and Hardware circuit is given. In terms of software design, the Enumeration process of the HID device descriptor is analysed. According to the main program flow chart, a local single-chip part of the main program is given. Through hardware and software debugging, the mouse functions of the left and the right button are successfully simulated.