In the integer pixel correction searching for three-dimensional digital speckle, the epipolar constraint and the projective rectification principle are used to constrain the correlation searching range from the whole image to the same horizontal line after projection rectification, and then the disparity constraint is used to reduce the searching scope. The correlation searching process is time-consuming. A novel integer pixel correlation searching method for three-dimensional digital speckle based on gray constraint is proposed, which is based on projective rectification and disparity constraint. The proposed method can remove most of the candidate matching points in parallax scope. When the number of valid points is 85783, the size of the correlation window is 9 pixel×9 pixel, and the correlation searching time is reduced from 7.24 s to 2.15 s. Experimental results show that the efficiency of integer pixel correction searching for three-dimensional digital speckle can be improved greatly.