Abstract: Surface error and alignment aberration of mirrors are required precision uniform in space transmission coaxial three mirror system alignment. Based on force analysis and system simulation methods for efficient alignment of the coaxial optical systems, one coaxial three mirror system with large aperture and long focal length was used to illustrate the relationship between aberration characteristics to alignment aberration and surface error. The spherical aberration, coma and astigmatism caused by alignment aberration and surface error were calculated, then wavefront RMS was used as an evaluation standard for system imaging quality. Finally, the weight of alignment aberration and surface error to system imaging quality were obtained. Based on the calculated result, the average RMS was adjusted to below 0.06. The lens alignment results demonstrate the possibility and effectiveness of this method, and the proposed methods could be available to shorten the alignment process, and promote system alignment accuracy.