介绍了杂散辐射的概念及其对光学系统成像质量的影响。以一透视式红外系统为例，通过对系统的光机结构的合理简化，利用杂散辐射分析软件Light tools中已有的蒙特卡洛分析方法，对已建立的红外系统光机结构的三维模型进行光线追迹分析，得到了系统像面的照度分布结果。同时，基于辐射度学相关理论对该系统中各结构表面的热辐射进行了定量计算，分析了结构中不同组成部分对系统像面的杂散辐射影响，提出本文系统中前镜框内表面为主要杂散辐射源。针对分析结果，探讨了红外系统的杂散辐射抑制方法，提出的方法可为后续设计提供参考。

This paper introduces the concept of stray radiation and its influence on the image quality of a optical system. By taking a refractive infrared optical system as an example, it simplifies the 3D optical-mechanical system properly and uses the Monte-Carlo model built-in Light tools to analyze the stray radiation of the system and to obtain the illuminance distribution of image in the system. Meanwhile, it calculates the radiation of surfaces in different parts of the system, and compares their influences on the image quality of the system. Furthermore, it points out that the inter surface of fore frame in the proposed system is a main source of stray radiation. Corresponding to the results, this paper finally investigates the restraint ways for the stray radiation, which can be a reference for the following designs.