A vaccumizing relieving system comprises an electromagnetic valve controller and further comprises an electromagnetic valve, vacuumizing relieving equipment, a vacuum pump, a pipeline and an extraction opening. The electromagnetic controller is used for detecting the vacuum degree of the vaccumizing relievign equipment and meanwhile controlling the electromagnetic valve to be opened and closed andpower-on and off of the vacuum pump. The pipeline is used for communicating between the vaccumizing relievign equipment and the electromagnetic valve. The electromagnetic valve communicates with thevacuum pump through the extraction opening. The vacuumizing relieving equipment is an infrared detector dewar. The infrared detector dewar is mounted on a satellite platform.