The resolution of image intensifier samples with different limiting resolution, signal-to-noise ratio, and equivalent background illumination were tested under different illuminations to study the variation of the resolution of Super Gen.Ⅱ image intensifier. By analyzing the test data, the influence of limiting resolution, signal-to-noise ratio and equivalent background illumination on resolution under different illuminations were obtained. The results show that in the range of 5.10.2 to 5.10.3 lx, the resolution of the image intensifier with different performance parameters is identical to its limiting resolution, and the resolution does not decrease with decreasing illumination. In the range of 5.10.3 to 5.10.7 lx, the resolution differs from its limiting resolution, and the resolution decreases with decreasing illumination. In the case of resolution decreasing with illumination, the higher the signal-to-noise ratio and the lower the equivalent background illumination, the lower the rate of resolution decrease, and the resolution reamains relatively high. In the illumination range of 5.10.3 to 5.10.6 lx, signal-to-noise ratio has a greater influence on the resolution, whereas in the illumination range of 5.10.6 to 5.10.7 lx, the influence of equivalent background illumination is greater. As the image intensifier is mainly used in low light conditions, the resolution under these conditions is more important. To increase the resolution of the image intensifier in the illumination range of 5.10.3 to 5.10.7 lx, it is necessary to improve the signal-to-noise ratio and reduce the equivalent background illumination as well as the limiting resolution.