The p-type ZnO：Al films deposited by RF/DC magnetron sputtering at room temperature were treated by gaseous ammonia annealing. The characteristics were examined by XRD, FESEM and Hall measurement. The results showed that the films crystallized in the wurzite phase with a preferential orientation along the c-axis and the surfaces are smooth and dense without visible pores and defects over the film, and the grain size was about 40—60nm at the annealing temperature of 700℃. The Hall measurement showed p-type conduction with the high carrier concentration of 8346×1018 cm-3 and low resistivity of 25014 Ω·cm when the annealing temperature was 700℃.