Germanium(Ge) thin films is one of the most commonly used optical film in long-wave and medium-wave infrared. High packing density for enhancing the spectra stability and the quality of the optical thin film elements is extremely important. Using 99.99% purity of the Ge materials, Ge thin films were prepared by electron beam evaporation in about 5×10-4 Pa vacuum pressure at different deposited temperature, while deposition rate was monitored and demonstrated at 0.8 ~ 1.0 nm/s by quartz crystal oscillation controller. The thickness of the thin films on silicon substrate is about 0.8 ~ 1.0 μm. Using the Fourier transform infrared spectrometer to test the spectral characteristics of Ge thin films before and after the thin film suck tide, according to the wavelength deviation dispersion theory, the packing density is calculated. The results show that as the deposition temperature increases, the packing density increases from 0.74 at room temperature to 0.99 at 250℃.