By collecting interferograms of several fields of optical system by means of autocollimating interferometry,aberrations including spherical,coma,astigmatism,could be obtained from those interferograms. The misalignments of the system are then corrected according to the misalignment values calculated by gradual aberration optimization. This way is feasibility for correcting the misalignment of optical system. A three-mirror,unobscured,high-resolution optical system with large aperture,long focal length was aligned and the results of 0° field wavefront error of 0.094λ rms, +1° field of 0.106λ rms and -1° field of 0.125λ rms at λ=632.8 nm are obtained.