According to the imaging performance requirements of airborne optoelectronic system, starting from the detector pixel size, the influence of detector pixel size on detector performance parameters such as detector dynamic range, signal-to-noise ratio and modulation transfer function was researched. Further the influence of detector pixel size on overall performance parameters of optoelectronic system, such as resolution, signal-to-noise ratio, detection and recognition operating range was analyzed. Finally, the parameters of foreign typical airborne optoelectronic system and the selected detector parameters were listed. Through the analysis of relationship between performance parameters of the detector and overall performance parameters of the system, the suggestions on the selection of the detector pixel size and the typical value Fλ/d of the airborne optoelectronic system were obtained, that is, generally, in order to obtain the long-distance high image quality images, the airborne optoelectronic system gave priority to the large pixel detector, and comprehensively weighed the relationship between detector pixel size and system Fλ/d, so as to control the Fλ/d within 2.