The “cat-eye” effect of optical window can be effectively weakened by circular holes array for its modulation, meanwhile the imaging quality of “cat-eye” target can be affected to some degree. Considering that Modulation Transfer Function (MTF) could comprehensively evaluate the imaging quality of photoelectric equipment, this paper put forward the testing models of MTF for telescope and Low-light-level night vision. The digital test of MTF of these two typical “cat-eye” targets was realized by a digital test system of MTF for optical instrument. The test results show that the circular holes array can lead to fall of “cat-eye” targets’ MTF at full spatial frequency, and if the aperture is smaller and the holesarray is more compact, the effect on MTF of “cat-eye” target may be less. This conclusion can provide reliable experimental data to reduce the effect on imaging quality when designing structure of circular holes array.