This paper mainly proposes a positon compensation method for Brushless DC Motors with trapezodial Back-EMFs. Conventional compensation method of Hall sensors is very complex because of its moving hall sensors on motor body .In this paper, the bus voltage and bus current are used to obtain the commutation time of the BLDC motor, and the optimal advance angle is determined to achieve the purpose of correcting the Hall position. Finally, the feasibility and validity of the proposed strategy based on BLDCM is tested and verified in the three-phase two-conduction mode through the simulations .