In this work, an optimal procedure was proposed to prepare aluminum-doped zinc oxide (AZO) thin films with a sheet resistance of 17.03 Omega/sq by rationally optimizing oxygen partial pressure and substrate temperature. The results showed that increased temperature has an improving trend in the resistivity of AZO thin films while elevated oxygen partial pressure exhibited a deteriorating trend. With rising of substrate temperature in an oxygen-rich atmosphere, oxygen adsorption phenomenon gets stronger. Adsorbed oxygen atoms or molecules suppress the formation of oxygen vacancy and trap electrons, which is responsible for the increase of resistivity. Besides, atomic force microscope analysis indicated that surface roughness of AZO thin films decreases as increase of substrate temperature.