1. A method for adjusting a gamma curve for a display control system of a display apparatus, comprising: analyzing a pixel gray value distribution of each frame and a sub-pixel gray value distribution of each of a plurality colors; and dynamically adjusting at least a gamma reference voltage, a curvature and a function according to the pixel gray value distribution and the sub-pixel gray value distribution of each color, for increasing a gray level voltage number corresponding to pluralities of pixel gray values and sub-pixel gray values in at least a predetermined region which has a relatively larger statistical number or a relatively higher ratio, and decreasing a gray level voltage number corresponding to pluralities of pixel gray values and sub-pixel gray values in at least a predetermined region which has a relatively smaller statistical number or a relatively lower ratio.