Disclosed is a method for realizing gray levels of a liquid crystal display (LCD) device, which realize various gray levels by interworking a gamma voltage and a sub-frame. The method includes the steps of dividing a liquid crystal response time interval for a pixel during one frame into n sequential sub-frames, enabling the pixel and applying a gamma voltage having a fixed level to the pixel, filling electric charges in the pixel by using the gamma voltage during each of the n specific sub-frames, and disabling the pixel at an end time point of a predetermined ith sub-frame, the i being an integer, wherein an amount of light projected on the pixel is adjusted by regulating a time point at which the pixel is disabled during each of the n specific sub-frames.