In this paper, the structural, electrical and optical properties of Al-doped zinc oxide (ZnO: Al) thin films onto quartz substrates prepared by electron beam evaporation technique were studied. All samples are polycrystal with a hexagonal structure and c-axis preferred orientation. The intense UV emissions and weak deep-level green emissions were observed. The films show high transparency, conductivity and high carrier concentration. Van der Pauw measurements show that the films are n-type degenerate semiconductor. The lowest resistivity is 6.7×10(-4 )Ω·cm at room temperature. These films exhibit a carrier density above 1020 cm(-3). The conduction mechanism was discussed. The behavior of metallic conduction can be observed in the high temperature range.