Black matrix (BM) process of color filter (CF) will reduce the yield because of the presence of defects of BM lost. To reduce the scrap of BM lost that affects the cost of TFT-LCD, we used Design of Experiment (DOE) method to identify significant factors that cause BM lost. Further, we obtained the optimum processing parameters from the experimental results to reduce BM lost. It has been found that using the DOE approach with the optimum parameters would greatly improve both the processing capability of CF manufacturing and the conforming rate of the color image in display.