A driving circuit includes a plurality of reference voltage lines and a digital to analog converter. The reference voltage lines are configured for respectively transmitting different grayscale reference voltages, in which the grayscale reference voltages are divided into at least two groups, and the wire diameter/wire width of at least one reference voltage line among the reference voltage lines of a first voltage group among the at least two groups is different from the wire diameters/wire widths of the reference voltage lines of a second voltage group among the at least two groups. The digital to analog converter is coupled to the reference voltage lines to receive the grayscale reference voltages and is for converting a digital signal into a grayscale voltage according to the grayscale reference voltages.