Abstract: As a widely used terminal display, the luminance uniformity of LED display is an important factor for display quality. An algorithm of improving brightness uniformity on LED display is introduced based on the principle of display control and correction in this paper. The CCD (Charge-coupled Device) camera is used to grab the RGB images of display screen. The position of LED light is determined by using mathematical morphology and template matching. And then calculate the relative brightness of the light spot according grayscale value of light emitting region. Finally, generate the correction parameters of each light point and use pulse width modulation to control the brightness of light points. Experimental results show that this algorithm can improve the brightness uniformity on LED display effectively, thereby improving the quality of the display and increasing the life time of the display.