In direct torque control system, the PID controller is often adopted to be the speed adjuster. When disturbances are thrown to the motor, a long time is taken to renew the motor to steady state. In this paper, new auto-disturbance-rejection controller (ADRC) is introduced into direct torque control system. Instead of PID speed adjuster, ADRC speed adjuster is designed. The speed observer is designed based on model reference adaptive system (MRAS), too. The performance difference is analyzed between PID controller and ADRC in speed sensorless direct torque control system. The simulation results show that the AC speed adjustable system has speedier response performance, stronger disturbance-rejection performance when ADRC is adopted. Moreover, according to simulation results, there is smaller warp between motor command speed and actual speed when motor parameters perturb.