Abstract: Based on the phenomena that parallel rays will parallel move when parallel rays pass the oblique plate glass, the influence of three section type optical window on imaging resolution of aerial camera was analyzed. The focus of the aerial camera was 1 000 mm, the thickness of window glass was 25 mm, and the included angle between window glasses was 45. When the imaging distance was 5 000 m, the value of image offset was 3.34 m which was greater than the value of one-third pixel. The influence of image offset on imaging resolution was tested by experiment. The results show that the greater the focus, the thickness of window glass and the included angle between window glasses, the lower the imaging resolution. And long focus camera is not suitable for imaging under small imaging distance.