The embodiments of the present invention provide a film transistor and the manufacturing method thereof, an array substrate and a display apparatus, relating to the technical field of display and capable of effectively ensuring that while the on-state current is increased, the leakage current is reduced. The film transistor includes a gate electrode provided on a substrate, a source/drain pattern composed of a source electrode and a drain electrode, and an active layer, wherein the active layer comprises a first semiconductor layer and a second semiconductor layer arranged in layers, with the former having a larger electron mobility than the later and the former being closer to the gate electrode than the latter. The semiconductor layer at one side of the active layer and remote from the source/drain pattern has an extended part, compared with the semiconductor layer close to one side of the source/drain pattern, at a position corresponding to the source electrode and/or drain electrode. The source electrode and/or the drain electrode are in contact with the bottom surface of the semiconductor layer in the active layer close to one side of the source/drain pattern and extend to the extended part so that they are in contact with the extended part.