An aero-optical ground test platform based on the hypersonic (Ma= 6.0) gun tunnel was built. The test object was an optical dome model with cooling jet structure. Combined with background oriented schlieren technology, a high-speed camera was used to obtain the light deflection information of the flow field with five different pressure of jet value: 0, 04, 1.0, 1.16 and 1.8. And the corresponding modulation transfer function was calculated with the geometric optics theory. The experimental results show that the increase of pressure ratio of jet value can reduce the envelope area of the modulation transfer function of the flow direction and span direction. The flow direction modulation transfer function fluctuates between 2~ 4 lp/mm under larger pressure ratio of jet value.