This paper proposes a new image-processing system for measuring eye movement. The eye position can be determined by the method of Haslwanter (1995), which uses the coordinates of pupil center for each calibration position in the image plane. The center of the pupil in the image plane is calculated by the new algorithm using gray-level correlation. The point of this gray-level correlation algorithm is that the gray-levels of two symmetrical points have high correlation with respect to the center of the pupil. This system also measures pupil movement.