To improve spatial resolution of the image, a method for reconstructing high resolution image based on the independent equations of pixel grey level was proposed in this paper. An image sequence with low resolution was acquired through mechanical microscanning. The correspondence relationship of pixel grey level between the Image sequence with high resolution and the one with low resolution, which was acquired by displacing each time the image over the detector plane by a distance equal to half of the detector pitch, was analyzed. The independent equations of pixel grey level for high resolution images were set up, with which the high resolution image was reconstructed. Compared with other methods, results of simulation experiments show that the time taken in reconstruction with the algorithm is shortened from seconds to milliseconds. It lays the foundation for reconstructing super resolution video.