Abstract: Quartz crystal oscillation technique was applied to measure the increase of oxide scale on Nd film targets and Auger electron spectroscopy was used to analyze the depth distribution of oxygen and neodymium. Scanning electron microscopy, X-ray diffraction and X-ray photonelectron spectroscopy were used to characterize oxide scale. Results show that the environment where Nd films were stored plays a great role in the oxidation behavior of the Nd films. Water contained in the atmosphere is the key factor for the rapid oxidation of the Nd film. The scale is amorphous and shows steamed bread like surface. The small ratio of the oxide volumn to the metal volummn may be the cause of the Nd inclining to oxidation. The scale is covered by a layer of hydroxide. the thickness of the hydroxide is the