Abstract: In view of problems of serious loss and low efficiency of operation existed in induction motor of frequency-conversion speed-regulation system controlled by constant flux, the paper put forward a kind of efficiency optimization control scheme of mine frequency-conversion vector control system. Under two-phase d-q rotating coordinate system, the scheme established loss model of the system including set and rotor copper loss and iron loss, derived corresponding relationship between motor loss and rotor flux under different operating conditions. In order to solve problem of slow dynamic response of the system caused by weak magnetic operation, it optimized proportion of torque current and flux current to get fast response of electromagnetic torque and speed tracking of the motor. It established experimental platform of speed regulation system of 22 kW three-level induction motor based on DSP+FPGA control system, and the experimental results show that the optimized scheme can reduce loss of vector control system of induction motor, improve operation efficiency of the system, and ensure steady-state performance and dynamic response performance of the system.