A thin film transistor, a manufacturing method thereof, an array substrate, and a display panel are provided. The thin film transistor includes a semiconductor layer, a source and a drain. The semiconductor layer includes an active layer and a superhydrophobic layer. The active layer includes a source contact, a drain contact and a channel portion. The source corresponds to the source contact, and the drain corresponds to the drain contact. The superhydrophobic layer is disposed on a surface of the active layer proximal to the source and the drain. The superhydrophobic layer includes a plurality of multi-level nanostructures protruding from the surface of the active layer, and the superhydrophobic layer at least covers a channel portion of the active layer.