A resistor renormalization method for a source driving circuit is provided, wherein the source driving circuit includes a plurality of resistors coupled in series, and the resistors respectively have a resistance and correspond to a number section value. The resistor renormalization method includes the steps of: (A) adding the resistances of the resistors to generate a total resistance; (B) providing a radix, wherein the radix is a natural number; (C) dividing the total resistance by the radix to generate a calculated section value; (D) dividing the resistances of the resistors by the radix to generate a plurality of remainders, respectively, and adding the remainders to generate an accumulated remainder; and (E) setting the number section value and the resistance of each resistor according to a relation between the calculated section value and the number section value and a relation between the remainder of each resistor and the radix.