For the need in time and precision of SAR registration, the article advanced an algorithm based on corner feature that satisfied this need well. Extracted corners in both two images, constructed triangles using these corners, found the similar triangles by computing the angles of each triangle in two images and got the affine transformation coefficients by using the coordinates of six vertexes of two similar triangles in two images. Transformed the reference image using the affine transformation coefficients, compared the similarity of two images, and the transformed image corresponding to the maximum similarity was the registration result. Introduced the strong corner always used in video track into the experiment to verify the algorithm. The experiment data demonstrates that the algorithm is fast and accurate and has the ability of anti-noise to some extent.