X-corner detection is widely used in camera calibration. In this paper, a new algorithm for X-corner detection is proposed to cope with the problems of central symmetry and the light and dark alteration in the four regions around the center. The position of the corner can be determined exactly by detecting the change of the image gray and computing the correlation coefficient of the symmetry regions through the presented algorithm. Experiments show that the algorithm is easily implemented with the less computational cost. Furthermore, it is robust to the rotation transformation and brightness alteration of the X-corner image and is insensitive to the noise of the image.