The working environment of an infrared optical lens is complicated and often affected by external loads. A finite element analysis model is established in ANSYS for a long-wave infrared optical lens, and half-sine impact simulation analysis with a peak acceleration of 100g and duration of 6 ms is conducted. The rigid-body displacement, peak to valley (PV), and root mean square (RMS) values of the extracted data are calculated, and the Zernike polynomial is used to fit the lens surface shape after impact to estimate the Zernike coefficient. Correspondingly, the impact on the performance of the infrared optical lens is analyzed. Based on the response surface method, the infrared optical lens is optimized, simulations on the impact of the optimized model are conducted, and comparative analysis is performed. The results show that the maximum deformation and the maximum equivalent stress of the lens after impact are reduced due to the optimization of the infrared optical lens; additionally, the PV and RMS values, which represent the changes in the surface shape of the lens, decrease. Thus, optimizing the structure can reduce the impact to a certain extent.