Abstract: Taking the Siemens S7-300 PLC as the controller and a two-phase stepper motor as the controlled target, the design of a stepper motor control system based on PLC is realized. The control scheme of this design can monitor the operation status of the stepper motor and the I/O distribution of the PLC. The stepper motor control system uses multiple hardware buttons to conduct real-time control over the start, forward and reverse rotation, speed regulation, and shutdown of the stepper motor. In terms of software, the system takes STEP7 and KingView as the core, and the programming adopts ladder diagrams. Moreover, computer simulation and the KingView system are used for simulation and monitoring, endowing the entire system with an intuitive human-machine interaction interface, which enables real-time operation and monitoring of the site.