Aluminum nitride (AlN) thin films were deposited on (100) oriented silicon wafers substrates by Hollow Cathode Electron Beam Vapor Deposition system (HCEBVD) under various Ar/N2 mass flow ratio. The films were characterized by Atomic Force Microscopy (AFM), Glancing Incident X-ray Diffraction (GIXRD) techniques and Ultraviolet/Visible Spectrophotometer (UV/VIS). It was found that the thin films are polycrystalline and have a hexagonal wurtzite structure with (002) preferred orientation, as revealed by GIXRD. AFM analysis indicates that the surface of the thin films is smooth, with average RMS (Root Mean Square) roughness Ra of 0.7nm, which is suitable for application in surface acoustic wave devices. The film thickness and optical refractory properties of the AlN thin films were investigated.