The selection of materials,design and deposition of the waveband 7～14μm infrared antireflection on ZnSe substrate by ion beam assisted deposition are reported.The measured spectral curves of the antireflection film at 7～14μm deposited by this method are given．The experimental results show that the peak transmission of the film is more than 98%，the average transmission in the designed wavelength range is greater than 97%，the film adherence is good，the optical and mechanical properties are stable．These are critical for the application of infrared optical systems.