Abstract: In order to solve the humidity requirements of the camera in the satellite,the(application) study on the humidity control technique for the pressurized module is conducted by(experimental) verification and thermodynamic analysis.By the thermal test and in-orbit test of the satellite,it can be got that,by using the moisture of the camera's film,using humidity control(subsystem) and conducting humidity adjustment before launch,the relative humidity of the local area in the pressurized module of the satellite can be controlled in a range about 30%~60%,which meets the requirements of the camera.It is concluded from the paper that,the humidity control technique used by the thermal control system is successful,and ensure the full success of the(satellite's) task.