对经过低能离子束刻蚀前后的碲镉汞材料表面，测量其红外反射光谱，发现在刻蚀时间较短（＜１０ｍｉｎ）的情况下可以用扩散散射模型很好地解释刻蚀前后光谱的变化，由此方法得到的表面均方根粗糙度与材料和刻蚀条件没有明显的关系，约为６０～１００ｎｍ。这一结果为研究碲镉汞的表面形貌提供了新的手段。 The infrared reflectance spectra of HgCdTe surface before and after low-energy ion beam etching were measured. It was found that the diffusion-scattering model can be used to explain the change of the spectrum before and after etching under the condition of short etching time (<10min) , The root mean square roughness of the surface obtained by this method has no obvious relationship with the material and the etching conditions, which is about 60-100 nm. This result provides a new method for studying the surface morphology of HgCdTe.