Abstract: This paper a white balance algorithm based on the weight of pixels is proposed, and the algorithm is implemented by FPGA. Firstly, the RGB image is converted into a dark channel image, and the weight of pixels is achieved according to the dark channel value of the image and the distribution of the high light region. Then, the weighted mean of each channel is calculated according to the weight of each pixel, and the gain factor of each channel is obtained by combining the standard gray scale. Finally, the gain factor is used to adjust the white balance to eliminate the color deviation of the image. The experimental results show that the algorithm can effectively solve the problem of color cast of nighttime image and meet the requirements of real-time system.