A thin film transistor, a manufacturing method thereof, an array substrate and a display apparatus are disclosed. The manufacturing method includes forming a gate electrode (2), a gate insulating layer (3), an active region (4), a source electrode (5) and a drain electrode (6) on a base substrate (1) with the active region being formed of ZnON material, and implanting the active region (4) with nitrogen ion while it being formed, so as to make the sub-threshold swing amplitude of the thin film transistor less than or equal to 0.5 mV/dec. The manufacturing method reduces the sub-threshold swing amplitude of the thin film transistor and improves the semiconductor characteristics of the thin film transistor.