Aiming at the problem that parameters of induction motor are easy to change during operation,a rotor flux observer with feedback compensation was designed based on the idea of extended state observer,taking variable motor parameters as disturbance term.The sensorless vector control of induction motor was realized by model reference adaptive system.The rotor flux observer was used as the reference model in the model reference adaptive system,and the problem of pure integral drift of voltage-type flux observer was overcome.The simulation results show that the speed identification error of the proposed algorithm is 0.3%,the speed overshoot is 0.83% and the torque ripple is reduced by 38% when the mutual inductance of fixed rotor is 20%.The algorithm has good speed identification precision and anti-disturbance ability.