In order to realize the ZnO materials better in the application of the photoelectric devices,this paper studies the Ag/Au ohmic contact to n-ZnO thin films.Semiconductor char acteristic analysis system is used to measure the I-V characteristic curve. Dig dis c method is used to test the ohmic contact resistance rate.They reflect the influence of annealing temperature on the conta ct characteristics.Auger electron spectroscopy (AES) is used to study the microscopic structure of ohmic contact finally.The results show that Ag (50nm)/Au (100nm) ohmic contact to n-ZnO thin film is th e best when annealing temperature is 500℃.The as-deposited Ag/Au scheme shows a specific contact re sistivity of 2.3×10－2 Ω·cm－2.And the lowest specific contact resistivity is 5.2×10－4 Ω·cm－2.The specific contact resistivity shows a decreasing tendency with the annealing temperature up to 500℃.However,for the sample annealed above 600℃,the I-V curves reveal the characteristics of local bending,which shows rectification trends.Interface diffusions and reactions induced by anneal ing treatment are found to be responsible for the decrease of ohmic contact resistivity and the rectificati on trends.The reflection of Ag/Au characteristic is better than that with other metal depositions.