Non-Common Path Aberrations (NCPA) often exist in adaptive optics system, due to the discrepancy between sensing path and imaging path. A method for correcting NCPA was presented, which is very suitable for wavefront processors in forms of hardware. First, causes of NCPA were analyzed and NCPA examination with phase diversity was discussed. Then, according to the working process of wavefront processors, an algorithm which converts NCPA to reference spot shifts of the wavefront sensor was deduced, and a software module in main controller computer was programmed for implementing this algorithm. Finally, an experiment with a light source as a target was conducted in the optical path of a telescope. Experiment results show that energy concentration of the target image is increased by 17.6% approximately after NCPA correction with this method. The experiment proves that this method is capable of NCPA correction for adaptive optics system.