Tracking moving targets under variant illumination in a large range is still a hard problem in computer vision.In order to solve it,the illumination model is established based on the outdoor light source estimation,which is used to estimate the illumiation in tracking vision.Then the optical flow vector of the moving target is computed combining the image cutting algorithm,so the moving target is tracked.Experimental results indicate that the proposed scheme is adaptive to illumination changes,can track the moving target accurately,and improves the algorithm′s robustness.