The invention relates to a method for compensating for poor uniformity of a liquid crystal display having a non-uniform backlight. By virtue of selecting a standard color that all cells can achieve to serve as a virtually primary color, the invention measures to give the relationship between the tri-stimulus values of the virtually primary color and those presented by the respective cells and records the resultant values to serve as compensation data. During operation of a display, the input image data are computed based on the compensation data for respective cells in accordance with the cell locations and converted into compensated image signals. As such, all of the cells are able to present the same chromaticity and brightness upon receiving the same image signal, thereby performing uniform chromaticity and brightness across the entire display.