The present disclosure provides a thin film transistor which includes a source electrode, a drain electrode, a semiconducting layer, an insulating layer and a gate electrode. The drain electrode is spaced apart from the source electrode. The semiconducting layer is electrically connected with the source electrode and the drain electrode. The gate electrode is insulated from the source electrode, the drain electrode, and the semiconducting layer by the insulating layer. At least one of the gate electrode, the drain electrode, the source electrode includes a carbon nanotube composite layer.