A mid-wave infrared dual channel band-pass filter with good spectral property was designed by coating a mid-infrared band-pass filter film on Ge substrate one side and a mid-infrared negative filter film on the other side. Films were deposited by different processes,and the infrared transmittance of the filter was tested by infrared spectrometer. The results show that band-pass transmittance and the cut-off depth of rejection zone are both good. The change of evaporation angles and accumulation of layer thickness errors are main causes that there are two stronger second peaks in rejection zone and the middle of the rejection zone slightly shifts.