为了分析光学材料折射率非均匀性对极小像差光学系统成像质量的影响，从而指导系统的进一步优化设计，提出一种三维仿真和光线追迹方法。该方法是在Zemax中通过自定义的程序，构建材料折射率均匀性的三维分布，设置光线追迹的步长，并控制整个光线追迹的过程，以提高仿真分析的精度。利用所提出的三维仿真和光线追迹方法，对一个数值孔径为0.7、工作波长为632.8 nm、波像差均方根(RMS)值为1.5 nm的小像差光学系统进行了仿真分析。结果表明，相比于传统的二维处理方法，提出的方法仿真精度有较大提高。

In order to analyze the effect of optical material inhomogeneity on the image quality of optical systems with extremely small aberration, and guide the optimization of the optical systems, we propose a three-dimensional simulation and ray-tracing method. This method works in Zemax, using a self-defined program to build the three-dimension distribution of the material inhomogeneity. By setting the setp of the ray-tracing process and controlling the ray-tracing process, the simulation precision is enhanced. As an example, We study an optical system with numerical aperture (NA) of 0.7, wavelength λ=632.8 nm, wavefront aberration root-mean-square (RMS) value of 1.5 nm. The simulation result shows that the simulation precision of this three-dimensional simulation and ray-tracing method is obviously better than other two-dimensional methods.