The main contact sources and theory were introduced, and the reasonable finite element model was established. The nonlinear contact analysis method was used to analyze a small hammer (m=0.18 kg) with different height impacting pin, and the pressures applied to coneshape bores were obtained. Subsequently, the surface shape accuracy of the planar mirror was analyzed with both nonlinear and linear analysis methods. Then, the imaging experiment of the space plane mirror was carried out. The results of analysis and experiment indicate that the surface accuracy of nonlinear analysis is closer to experimental value than that of linear analysis, and the error of results between nonlinear analysis and experiment is 8.6%. Finally, one reasonable pin preload project of the space plane mirror assembly was proposed that small hammer maximum free fall height should not be larger than 25mm.