Embodiments of the present invention provide a thin film transistor (TFT) array substrate and a method for manufacturing the same and a display device. The TFT array substrate improves a structure of a TFT array substrate and has a small thickness, and process flow is simplified. The method for manufacturing a thin film transistor (TFT) array substrate comprises: obtaining a gate line and a gate electrode through a first patterning process on a glass substrate; forming a gate insulating layer on the gate line and the gate electrode; forming a graphene layer on the gate insulating layer, and obtaining a semiconductor active layer over the gate electrode by a second patterning process and a hydrogenation treatment; obtaining a data line, a source electrode, a drain electrode and a pixel electrode which are located on the same layer by a third patterning process; and forming a protection layer on the data line, the source electrode, the semiconductor active layer, the drain electrode and the pixel electrode.