Rare-earth Yb film targets were prepared on to glass substrates with electron-beam evaporation, and were exposed to various oxidation atmosphere. The valance, species, morphology and the structure of the oxide layer were studied with X-ray photon electron spectroscopy, Auger electron spectroscopy, and X-ray diffraction. The surface of the films is found to have a layer structure, with the oxide layer covered by a hydroxide layer and adsorbed layer. The hydroxide and oxide layer are amorphous, the water in the oxidation atmosphere is the key factor resulting the increase of the ytterbiun film oxidation rate.