To deal with commutation error in conventional position-sensorless control technology of the brushless DC motor, a closed-loop correction method based on rotor angle observer is proposed. By the systematic analysis of the commutation error mechanism, a rotor angle observer model is formulated to achieve the rotor position in real time. The total commutation error of the motor could be normalized to the phase difference between the back EMF and the phase current for correction. Compared with the traditional position-sensorless control technology, the proposed method can accurately correct the commutation error in a wide range of motor speed and have the advantage of higher robustness. Extensive simulation and experiment results show that the proposed commutation error correction strategy can obtain accurate commutation points and significantly reduce the torque ripple. Especially, during the commutation period, the phase current ripple after correction is decreased from 42% to about 18% .