In this paper, the opto-mechanical structure design and passive athermalization design for the visible-light zoom lens of space-based photoelectric countermeasure platform are carried out. According to the working temperature index requirement of -20-50 ℃, an integrated opto-mechanical-thermal analysis of the zoom lens is carried out. Patran software is used to load the temperature stress on the lens, and calculate the thermoelastic deformation of the optical structure. Nastran software is used to calculate the rigid body displacement of the mirror nodes of optical components after thermal deformation. The Zernike coefficient of each lens surface after deformation is analyzed by Sigfit optical interface software, and the results are imported into Zemax to predict the effect of lens surface change and rigid body displacement change on modulation transfer function (MTF) and wavefront difference. Experimental results show that under the temperature load of -20-50 ℃, the maximum axial displacement of posterior fixation group can reach 6.107×10 ^-3 mm, which seriously affects the imaging quality. In order to reduce the influence of temperature load, flexible pressure ring is used to realize the design of axial displacement controllable heat difference dissipation. Integrated opto-mechanical-thermal analysis show that the MTF values of the optical system under temperature load are all greater than 0.3, meeting the technical requirements. Finally, the temperature adaptability of the zoom lens and the accuracy of integrated opto-mechanical-thermal analysis are tested by temperature reliability experiment, which provides a set of efficient, accurate, and wide-ranging integrated opto-mechanical-thermal analysis process.