ZnO:Al thin films were deposited on glass substrates by r. f. magnetron sputtering. The crystal structures were characterized using X-ray diffraction. The electrical property and the light transmission of the ZnO:Al thin films were investigates utilizing Hall system and UV/Vis/NIR spectrophotometer. The results show that the ZnO:Al thin films prepared with the sputtering power of 100W, working pressure of 0.3Pa and substrate temperature of 250°C have the resistivity as low as 3.1×10-3Ω⋅cm and transmittance over 90% in visible region. From the GIXRD patterns, higher electrical conductivity is related to the higher ratio of I2 (103)/I(002), which is a new reasonable structure parameter to estimate the electrical property of ZnO:Al thin films.