In order to solve the problems in the alignment of the off-axis aspherical optical system,the relationship between system wavefront aberration and Zernike coefficient is investigated based on vector aberration theory. The model of off-axis paraboloidal mirror and misalignment optical system is built. By collecting interferograms of several fields of optical system by means of autocollimating interferometry,the Zernike coefficient of coma and astigmatism can be obtained from those interferograms. Compared with the coefficients calculated by the software,the changes of the Zernike coefficients are obtained and the misalignment values of the system are then calculated with the model. The feasibility of this model using the CODE V software is analyzed. The results demonstrate that the alignment scheme is feasible and guidable to the alignment of complex optical system.