In this paper, we aim to improve the opening rate of color film substrate by proximity exposure mechanism, and carry out OPC (Optical Proximity Correction) at the corners of the pattern on the photo mask version, and DOE (design of experiments) to verify the optimal solution under the existing equipment and process conditions. The final result is that the color film black matrix pattern is closer to the design, and the substrate opening rate is increased by 1‐4%, which increases the product transmission rate and enhances the competitiveness of the product.