ZnO-based Thin Film Transistors (ZnO-TFTs) were fabricated by Radio Frequency (RF) magnetron sputtering successfully, and the temperature dependence and influence mechanism of the electrical characteristics of ZnO-TFTs are investigated. With the increase of the test temperature in the temperature range from 27 ℃ to 210 ℃, the on/off current ratio and the threshold voltage of the ZnO-TFT decrease significantly, and the subthreshold swing increases obviously, and the carrier mobility increases firstly and then decreases gradually. The change of electrical properties is mainly due to the combination effect of the increase of carrier concentration, the generation of point defects, and the enhancement of interface scattering in the channel active layer caused by the temperature increase. In addition, when the device is instantaneously cooled to the initial temperature, there is a hysteresis in the electrical characteristics. The main reason is that the recombination process need take a long time to reach the initial state for the generated point defects and interstitial oxygen atoms in the active layer caused by high temperature on the heating stage.