A method for generating a gamma table is provided. The method is applied to a display, and the display obtains n-bit corrected gray levels [y(1), . . . , y(2m)] from m-bit original gray levels [x(1), . . . , x(2m)] by using the gamma table, wherein m and n are positive integers. The method comprises calculating the corrected gray levels [y(1), . . . , y(2m)] corresponding to the original gray levels [x(1), . . . , x(2m)] according to a gamma curve; and successively calculating differences of two adjacent corrected gray levels (y(i+1)−y(i)) and recording the differences as a plurality of gamma reference values z(i+1) (i=1˜(2m−1)) corresponding to the original gray levels x(i+1), in which the value z(1) corresponding to x(1) is y(1), in order to generate the gamma table.