Provided are a thin film transistor structure, a manufacturing method thereof, and a display device. The method comprises: providing a substrate (10), and sequentially forming a gate (20), a gate insulating layer (30), an active layer (40), a doped layer (50), a source (610), a drain (620) and a channel region (70) on the substrate (10); placing the channel region (70) in a preset gas atmosphere for heating treatment; wherein, the channel region (70) is placed in a nitrogen atmosphere to heat for a first preset time, in a mixed atmosphere of nitrogen and ammonia to heat for a second preset time, in an ammonia atmosphere to heat for a third preset time; or first heating the channel region (70) for a fourth preset time, finally placing in the ammonia atmosphere to heat for a fifth preset time.