针对极轨气象卫星FY-3C载荷可见光扫描辐射计（VIRR）在轨红外定标时存在温度反演不一致的现象展开分析，提出了一种全链路自动化仿真分析方法，将仪器结构与卫星轨道参数和卫星平台环境相结合，通过对光机模型的高精度光线追迹来得到杂散光影响的定量化结果。仿真模拟了在轨红外定标和太阳光入射两种情况，确定了太阳杂散光的入射路径，解释了温度反演不一致的原因。将仿真结果与卫星在轨数据进行比对，验证了仿真方法的有效性。该方法可用于同类型载荷的在轨杂散光分析仿真工作，同时也为历史数据的再定标修正提供参考。

The temperature inversion inconsistency phenomenon is analyzed for the on-orbit IR calibration of Visible and InfraRed Radiometer (VIRR) which is a payload onboard polar-orbiting meteorological satellite FY-3C. A specific methodology, i.e., the whole chain automatic simulation and analysis, is proposed. This method involves the orbital parameters and the satellite platform environment. By means of the ray trace of the opto-mechanical structure with high precision, the quantified effect of solar stray light is obtained. The simulation includes on-orbit IR calibration and solar incidence, resulting in the identification of the incidence path of solar stray light as well as the explanation for the temperature inversion inconsistency. Through the comparison between the simulated results and the on-orbit data of the satellite, the effectiveness and the validity of the method are verified. This method can be applied to the simulation and analysis of on-orbit stray light effect of the same-typed payloads. This work can also provide references to the recalibration of historical data.