A method for constructing a Gamma table to perform Gamma correction according to the Gamma table. First, select (2.sup.M+1) major sampling pixel data, which divide a Gamma curve into 2.sup.M major segments. Next, obtain the maximum difference between the n-th major sampling line and the n-th major Gamma segment; according to the maximum difference, select (2.sup.Rn-1) minor sampling pixel data from the n-th major Gamma segment. Last, store the Gamma corresponding relationship of all major and minor sampling pixel data in the Gamma table. The execution of Gamma correction includes the following steps. First, select the a-th major sampling pixel datum according to the first M bits of an input pixel datum. Next, select the b-th and the (b+1)-th minor sampling pixel data according to the (M+1)-th bit to the (M+R.sub.a)-th bit of the input pixel datum. Finally, obtain the Gamma corresponding relationship of the input pixel datum via interpolation using the b-th and the (b+1)-th minor sampling pixel data.