The high quality ZnO: Al films were successfully produced by DC reaction magnetron sputtering technology. The Al-doping effect on electrical and optical properties and its scattering mechanism are discussed in detail. The analyses of X-ray diffractometer (XRD) , X-ray photoelectron spectroscopy(XPS) and high resolution Auger electron spectroscopy (AES) show that Al2O3 could be effectively removed by controlling oxygen flow and Al-doping concentration during deposition of ZnO : Al films. Zn, Al and oxygen elements are well distributed through the films. For highly degenerated ZnO:Al semi-conductive thin films, the theoretical and experimental results reveal that the ionized impurity scattering dominates the Hall mobility in the films in the low-temperature range, while the lattice vibration scattering becomes a major scattering mechanism in the high-temperature range. The grain boundary scattering only plays a major role in the ZAO films with small grain size (as compared to the electron mean free path). The high quality ZnO: Al films were successfully produced by DC reaction magnetron sputtering technology. The Al-doping effect on electrical and optical properties and its scattering mechanisms are discussed in detail. The analyzes of X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and high resolution Auger electron spectroscopy (AES) show that Al2O3 could be effectively removed by controlling oxygen flow and Al-doping concentration during deposition of ZnO: Al films. Zn, Al and oxygen elements are well distributed through the films For highly degenerated ZnO: Al semi-conductive thin films, the theoretical and experimental results reveal that the ionized impurity scattering dominates the Hall mobility in the films in the low-temperature range, while the lattice vibration scattering becomes a major scattering mechanism in the high-temperature range. The grain boundary scattering only plays a major role in the ZAO films with small grain size (as compared to the electro n mean free path).