非成像光束在光学系统内表面的多次折射反射容易在像面附近形成光晕或鬼像，变焦系统由于镜片多，机构复杂等往往难以进行全面的分析模拟。利用ASAP软件模拟每个透射面作为部分透射、部分反射的表面，对变焦光学系统非轴上光进行分析，模拟出变焦系统的光学元件表面和光机内壁，实行实际光线追迹，然后以像面为研究对象，进一步实施实际光线追迹,模拟出全部散射光在像面上的能量分布，找出鬼像形成的原因，并在此基础上通过改变二次反射所在面的曲率或改变所在面的折射率两种方法对变焦光学系统进行优化，减小鬼点数目，以提高系统的成像质量。

The stray light which is generated by the residual multi-reflection on the surfaces in optical system easily forms ghost images near the image plane and they influence the acuity and contrast gradient of images, decrease the resolution of lens, and disturb the target discrimination. It is difficult to be simulated and analyzed due to the excessive surfaces, complex structure and locomotory parts in zoom lens. All the transmission planes taken as the partial reflection and partial transmission planes were simulated with ASAP（advanced system analysis program）and the stray rays on dangerous surfaces which easily generate the ghost images in zoom lens were analyzed. Based on it, the zoom lens was optimized and the quality of image was improved by changing the curvature and refractive index of the second reflection planes.