Abstract: The microstructure and morphology of the lead telluride optical thin films prepared by ion beam assisted deposition（IBAD） were observed by atomic force microscopy（AFM）.The results show that lead telluride thin film deposited by conventional evaporating method assumed a kind of laminated structure,and ion bombardment can change the microstructure of thin film significantly,result in the disappearance of laminated structure and growth up of crystalline grain.