Abstract: According to the characteristics of the highly comparability of histogram by contiguous field of video image, an improved histogram equalization algorithm for video image processing system is proposed. This paper validates the improved histogram by using MATLAB emulation and implement it based on FPGA video image processing system. The experiment indicats that the improved algorithm realize iamge enhancement, predigests the structure of system and complexity of logistic design, saves thirty percents hardware cost and meets currently standard video image for the real-time requirement.