Star target detection is influenced by many environmental factors during daytime. Star target detection at the condition of different parameters is analyzed in an ideal environment and the presence of clouds. Infrared radiation is also influenced by uncertain factors such as rain and fog except the main influence factor such as clouds during the transmission in atmosphere. These two uncertain factors are researched. The presence time of rain and fog, place and height are all uncertain factors. Incorporating with the existing experience formulas, radiation attenuation states at the condition of different parameters are analyzed. The influence from rain and fog on radiation transmission is quantified.