Aiming for remote wide-area detection of weak and small aerial target under space-based complex observation conditions, we in this paper analyze the radiation interaction mechanism between complex background environment, e.g., solar illumination, clouds and earth surface, and aerial target based on the full link of space-based optical detection. We then summarize main environmental factors that affect the target radiation characteristics. After that, combined with the detectability characterization, we investigate the influence rules of environmental factors, e.g., different illuminations, various surface background types and clouds, on the target detection performance under different detection spectrum. Finally, taking a typical target as an example, we combine existing target characteristics cognition and theoretical modeling to rank the influence order of different environmental factors, and give the detection spectral optimal selection suggestions according to the variation of signal-to-noise ratio and the variation characteristics of the spectrum. This provides theoretical basis and scientific guidance for the design of stealth/anti-stealth aircraft, space-based detection system and information processing optimization algorithm.