An exemplary LCD includes a frame memory configured for receiving a plurality of first gradations of current frame and outputting a plurality of second gradations of preceding frame pre-stored therein; a comparator configured for receiving, comparing the first gradations with the second gradation to generate a comparison result; a luminance detector configured for detecting a luminance degree of each of pixel according to the gradations of current frame; a calculator configured for calculating a complication degree of a picture to be displayed in current frame; and a gradation processor configured for receiving the first gradations of current frame to be displayed on the LCD panel, generating a plurality of pairs of compensating gradations according to the gradation of each pixel, and selecting one pair of the compensating gradations to be outputted to the LCD panel according to a received comparison result, a received luminance degree, and a received complication degree.