把影响椭圆弯晶谱仪波长判读误差的因素分为两种：一种是未通过椭圆前焦点的射线被理想椭圆晶面衍射时形成的误差；另一种是只考虑晶体为非理想椭圆晶面形成的误差。分别对这两种模型进行了分析，并通过数值计算给出狭缝对椭圆弯晶谱仪波长判读误差的影响关系。模拟的数据与其他人的实验结果吻合较好。 There are two kinds of factors that affect the interpretation error of wavelength of elliptical Bending Crystal Spectrometer: one is the error formed when the ray that does not pass the front focus of the ellipse is diffracted by the ideal elliptic crystal plane; the other one is that only the crystal is considered as the non-ideal elliptic crystal Surface formation error. The two models are analyzed respectively and the influence of the slit on the interpretation error of the wavelength of the ellipsometer is given by numerical calculation. The simulated data are in good agreement with the experimental results of other people.