Abstract: On the basis of analysis on the characteristics of the control objects in the thermal vacuum tests and the current problems and difficulties in the temperature control, an adaptive PID controller is designed. In order to verify this control method, two thermal vacuum tests are carried out. The test results show that this adaptive PID control method enjoys many advantages, including small amount of overshoot and superior adaptability without the need of manual operation in the test. It provides a better solution to the problem in the current control system with the lack of automation and a large overshoot, and thus greatly reduces the labor intensity of manual adjusting.