Mine hoist is the necessary equipment in mine, its reliability and safe means a lot to mine production. The application of PLC can improve the reliability and safe of mine hoist. Through the study of PLC application in mine hoist variable frequency speed control system, variable frequency speed control system hardware structure diagram based on PLC, its working principle and main function were introduced; The main control circuit of software flow chart was pictured, the whole process was introduced. PLC with good frequency control and mechanical characteristics could meet the requirement of mine hoist operation under special working environment and made the system safe and reliable.