This article discusses the existing problem of traditional PLC ( programmable logic controller) experimental teaching, the simulation experiment's superiority and the reasonable application in the PLC teaching. Configuration software is used to simulate external equipment of the controller. The result of PLC program can be display directly. Reasonable arrangements for the simulation in the appropriate stage of the teaching, Enable students to experience the real control process, Enrich the content of practice teaching, the simulation experiment may enhance student's study interest and innovative ability effectively.