The co-sputtering AZO target with Sn target is used to prepare Al-Sn co-doped ZnO (ATZO) thin film samples by radio frequency (RF) magnetron sputtering. The ATZO films are annealed at different temperatures: 300, 350, 370, 400, and 500 ℃ and with different processing time: 1, 2, 4 h. X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to analyze their morphology and composition. The results show that the ATZO thin films are hexagonal wurtzite structure with (002) preferred orientation and the surfaces of the samples are evenly smooth. The optical property of samples measured by the UV-vis spectrophotometer shows that the sample annealed at 370 ℃ for 2 h has the highest average transmittance of 87.09% at the wavelength of 400—760 nm, and the corresponding optical band gap is 3.40 eV. Meanwhile, this sample has the lowest resistivity value of 4.22×10-2 Ω·cm, the highest carrier concentration of 6.44×1020 cm-3 and mobility of 4.30 cm2/(V·s), respectively.