Abstract: Detecting and calculating accuracy of centroid of focal spot affects the detecting accuracy of Hartmann-Shack wavefront sensor. Noise will reduce the detecting accuracy when the whole sub-aperture is used as the detecting window. The influence of window selection on centroid detection error is great. In this paper, the method of optimizing detecting window based on traditional algorithm is proposed in order to improve the detection accuracy. Computer simulation indicates that the detection error can be decreased. Also, an optical system for distorted wavefront measurement is built with array Fresnel zone plates as the wavefront sensor. The experimental results show the accuracy of centroid detection is improved. The rms value of the error for reconstruction wavefront with high noise can be