On the basis of summing up conventional testing methods for the radius of curvature of optical sphere, a novel method using laser tracker and interferometer is proposed. The focus of the exit spheric surface wave front and the coordinate of curvature center of the testing spheric surface are tested by a laser tracker. After adjusting the spheric surface and the interferometer, the coordinates of many points on the spheric surface are tested, and then the radius of curvature of the spheric surface can be calculated by the data. The basic principle and theory of the method are researched, and the synthetical optimization method for testing radius of convex spheric surface is proposed. An optical lens with the aperture of 400 mm is tested by the method. The radius of the convex surface is measured to be 1022.283 mm, and that of the concave surface is 4069.568 mm. For comparison and validation, the spheric surface is also tested by a profilometer, and the relative errors for both surfaces are less than 0.05%.