Abstract: Optical flow method is a mathematical analysis of the relationship between the visual sense and its object. It has been widely applied successfully in related areas of image recognition and tracking. This paper introduces the basic concept and principle of optical flow method by examples such as the Horn-Schunck and the Lucas-Kanade method, and then on the basis of further using the unified variational method to explain the vast majority of optical flow field algorithm. Finally, it introduces the application of the optical flow method in the field of meteorology and its prospects.