In this paper, ZnO:Al transparent conducting films were prepared on glass substrate by magnetron sputtering from Al doped ZnO ceramic targets. By measuring and analyzing the structure and electrical properties of films in front of targets at different target-to-substrate distance, it was concluded that the bombardment of energetic oxygen negative ions decreased with increasing target-to-substrate distance, dominating variation of resistivity and the microstructure in erosion area, while numbers of active oxygen decrease with increasing target-to-substrate distance, explaining variation of resistivity in non-erosion area. The influence of target-to-substrate distance on electrical and microstructure properties of ZnO:Al films on drum was also investigated in order to confirming our result. The result indicated that both energetic oxygen negative ions and numbers of active oxygen determined the properties of films on drum. While target-to-substrate distance is less than 95 mm, the numbers of energetic oxygen ions are the key factor and vice versa. The optimum resistivity of post-annealed films on drum was 5.1 x 10(-4) Omega cm at target-to-substrate distance of 95 mm. (C) 2012 Elsevier B.V. All rights reserved.