Al-Cu thin films were deposited by DC magnetron sputtering. The films are characterized by atomic force microscopy and its surface morphologies are analyzed by wavelet technique. Multiresolution signal decomposition wavelet technique was employed to extract the surface roughness from the AFM images of Al-Cu thin films. It is observed that the Al-Cu thin films exhibit higher surface roughness value with increasing deposition time. The calculated surface roughness of the thin films, using wavelet technique, is comparable with that of its experimental values. © 2009 World Scientific Publishing Company.