This paper researches the calculation method for the change of space intersection angle of a mapping camera, for the change of the angle should be within 5″ to ensure the reliability of transmitting data in orbit. First, the temperature field was calculated for high and low temperature operating conditions with the I-deas software. Then, the calculated temperature field was input to a structural model as temperature load to complete the temperature mapping from a temperature model to the structural model, namely, from a simple model to a complex model. The thermal-elastic deformation was calculated and the center of optical element deformation was obtained. Finally, the change of space intersection angle of the mapping camera was calculated in two operating conditions with a self-programming software. The results show that the change of intersection angle is below 5″ when the temperature operating condition is changed. It concludes that the calculated method can get the accurate change of intersection angle and the calculated data can benefit to the analysis on the space mapping.