XPS, Raman spectrum and infrared transmittance spectrum were used to study the surface of Ge window on infrared detector, which was electron-aged in ultravacuum after some time. And Ge window was covered with a thin film of ZnS. Comparing the experimental result of the detector window of non-electron aged with the result of the one after electron aged, it is shown that the sorbate of detector window perhaps comes from easily deflating parts in vacuum chamber, such as connection wires′coats.