A method of performing gamma correction for LCD panels includes: dividing the display area of a LCD panel to form n sub-areas of the display area; dividing all grey-scale images into n sets to form n sets of grey-scale images; displaying a first chosen grey-scale image of each set of grey-scale images on the corresponding sub-area of n sub-areas concurrently; detecting the brightness of the first chosen grey-scale image with a photosensor installed on the sub-area; examining if there is grey-scale image pending for detection in the set of grey scale images; extracting a gamma curve of the LCD panel; and correcting the gamma curve of the LCD panel.