In order to avoid the influence of the ambient temperature change on the projection image quality of the infrared dual-band target simulator, the integrated optical-structural-thermal analysis of the zoom projection lens of this simulator is conducted. The finite element analysis model of the zoom projection lens is established. By the quasi-static treatment to the unsteady thermal stress, the thermal analysis and the statics analysis are finished. The displacement nephogram of overall unit versus temperature is also obtained. The discrete node coordinate data are converted into the vector deformation data by the finite element data conversion algorithm. The surface thermal deformation of each lens is fitted by the Householder algorithm based on the Zernike polynomials. If the fitting coefficients are imported to the optical design software, the thermal analysis results of the zoom projection lens under different temperatures can be obtained. The results show that the projection image quality is insensitive to the thermal deformation of the overall unit when the temperature is in the range of 10-30 ℃.