A TFT, a method for manufacturing the TFT, and an array substrate are disclosed. In the TFT according to the present disclosure, the nano conductive points that are independent from one another are formed in a channel area of the active layer, so that the channel area of the active layer can be divided into a plurality of sub channels that are independent from one another, and an equivalent electric field strength thereof can be increased. The larger the equivalent electric field strength is, the higher the carrier mobility ratio would be, and the larger the saturation current of the TFT would become. Therefore, the TFT with a higher definition and a higher aperture ratio can be manufactured.