The sensorless DTC of Brushless AC (BLAC) machine using Luenberger observer is proposed in this paper. In Direct Torque Control (DTC), accurate rotor position information is not essential. The speed is estimated by Luenberger observer, which used to improve the performance of dynamic tracking and accuracy of the whole system. The speed regulation is realized by a conventional PI regulator. Simulation results shows small overshooting and good dynamic of the speed and torque, low ripples in torque and flux. So we verify the effectiveness of the proposed observer to monitor the drive.