Dark channel prior haze removal algorithm is very simple and effective for single image haze removal, but it’s somehow limited by color distortion in gray areas and expenditure of time. Firstly, aiming at solving color distortions, we propose a modified dark channel prior haze removal algorithm. We correct the transmission of the gray areas by introducing the correction parameter, and the transmission is unchanged when the areas meet the law of dark channel prior. Secondly, to realize real-time haze removal for video surveillance, we use GPU to parallel accelerate and optimize the new algorithm on Compute Unified Device Architecture platform released by NVIDIA. Experiments show that the modified algorithm works effectively in gray areas. At the same time, the processing speed of images with a resolution of 640x480 can reach 37 frames per second after GPU acceleration and can also obtain the real-time haze removal result.