During the ascent of the airborne camera, due to the temperature drop and the thermal conductivity of the material of each part of the lens, the lens portion can have a temperature gradient, which causes the aspherical optical system to produce a gradient index. Using the finite element analysis software to perform transient thermal analysis on the lens part to simulate the temperature change during the ascent of the airborne camera, the finite element analysis of the temperature distribution results of different time nodes was introduced into the prepared refractive index gradient coefficient fitting program, and the solution was solved. The gradient index coefficient established the optical system model in the optical software through the mirror type interface, and use the speckle radius of the dot-column diagram to evaluate the influence of the image quality on the gradient index of the different time nodes. The results show that the temperature gradient of the airborne camera is the highest when it is lifted into the working height, and the influence on the imaging quality is also the most serious. The gradient refractive index coefficient decreases with the decrease of the temperature gradient coefficient, and the imaging quality is improved, which has guiding significance for the optical system design.