In this paper,we use the APSYS software of Crosslight Company to simulate the spectral crosstalk of different structures of themedium-wavelength / long-wavelength (MW/LW) two-color HgCdTe infrared detector in a quasi-plane structure.It is found that increasing the thickness of the medium wavelength layer will suppress the spectral crosstalk of medium wave to long wave,while increase the spectral crosstalk of long wave to medium wave by a small amount.The larger the composition of the barrier layer,the larger the conduction band offset between the barrier layer and the medium wave layer,the less the probability that photo-generated carriers will jump through the band offset barrier,which reduces the spectral crosstalk.The larger the thickness of the barrier layer,the lower the quantum tunneling effect,resulting in a reduction in spectral crosstalk.By optimizing the device structure,the spectral crosstalk of medium wave to long wave and long wave to medium wave can be controlled below 2.5 %.