Abstract: The computer optical elements (COE) are pure-phased elements, which can shape the laser beam to arbitrary shape, but is very complicated in their processing technic. Now some methods to realize the COE by digitized elements turn up, but the interference from the black-matrix effect is nonnegligible when using these methods. The influence of the black-matrix effect on the certain elements was researched by means of the Fourier optics theory, the factors to influence the black-matrix effect were found out and the corresponding simulation was carried out with MATLAB. The result shows that the energy concentrats to the center of the receiving screen when reducing the width of the black-matrix, and then the interference of blackmatrix effect is decreased effectively.