The undesirable phenomenon of edge dark band of TFT-LCD is introduced, the mechanism and influence factors are studied, and the optimum process parameters are concluded. The experimental results show that, from the perspective of panel design, the uniform thickness of edge cell gap is helpful to improve the uniformity of brightness in the edge area, and therefore the moderate amount of liquid crystal, the moderate size and doping ratio of silicon ball, and harder sealant are preferred. Meanwhile, the flatter the panel after polarizer attachment, the lighter the degree of dark band. From the perspective of backlight unit, the edge brightness uniformity of finished products has strong correlation with the batch of backlight. However, this is mainly related to the dimension parameters such as flatness of the backlight rather than the degree of dark band of the backlight. In addition, the aging process releases the internal stress generated during the assembly of backlight with panel, and alleviates the deformation at panel edge. Therefore extending the aging time appropriately is conducive to reduce the incidence of edge dark band. Through the application of optimum conditions, we have successfully improved the uniformity of edge brightness of our product and effectively enhanced its competitiveness.