It's difficult for all-time star sensor to avoid being affected by the atmosphere when conducting observation missions in the atmosphere. In order to conduct in-depth research on the reasons that make it difficult for all-time star sensor to observe stars during the day, it is necessary to analyze the atmospheric impact on the all-day star sensors during the imaging process. Utilizing MODTRAN software for simulating atmospheric interference, a comprehensive study was conducted on the atmospheric effects under different observational conditions, resulting in the development of a computational model for the atmospheric impact on all-time star sensor imaging. The research results show that selecting an appropriate spectral range is beneficial for daytime star observation tasks of all day star sensors. Based on the blackbody radiation law, constellations, and stellar spectral types, the calculation of stellar radiation has been revised, and a stellar target spectral radiation calculation model has been established. Finally, using the obtained atmospheric impact calculation model and the modified stellar target spectral radiation calculation model, combined with relevant detection parameters, the simulation signal-to-noise ratio and simulation star map are calculated. The correctness of the proposed model was verified by comparing the simulation results with actual experimental results.