Abstract: In this paper a window function acousto-optic correlator which includes one AOD is given. It can complete the correlation between the window function of a filter and the amplitude modulation function of a electric signal. We have done a interference-free experiment for a imitative back wave singal, which is composed of a rect pulsed radar signal with signal carrier-frequency and a radom interference signal without modulation. When the pulse width of the radar signal is 2 μs, the correlation gain is 15 dB.