Liquid crystal drop process is the key to the TFT -LCD technology. Generally, the selection of liquid crystal drop amount of products refer to the range of liquid crystal without cold bubble and gravity Mura, that is, LC Margin. The narrower the margin is, the smaller the range of upper and lower limits of the liquid crystal center distance of the product, and the cold bubble and gravity Mura are liable to occur during the process fluctuation. In this paper, a method of liquid crystal drop by panel is proposed according to the PS height of color filter for products with narrow LC Margin (≤3%). There is no cold bubble and gravity Mura in the test of high and low temperature during the production process with this method, at the same time, the liquid crystal dropping process was optimized. It provides a new solution for products with narrow LC Margin.