Abstract: Aiming at the existed shortage of great running consumption that main mine hoist system of one coal mine used speed-regulation mode of serial rotor resistance of motor,the paper proposed a reform scheme of cascade high-voltage frequency-conversion with multi-level based on H-bridge power unit for electric control system of hoist,introduced structure and main technology characteristics of PLC technology control system of hoist and basic principle of implementation of frequency-conversion driving system.The practical application showed that the reformed high-voltage frequency-conversion system of mine hoist ran stably and achieved design demand completely.