A thin-film transistor and a manufacturing method thereof, a display substrate and a display device are disclosed. The thin-film transistor includes a control gate, a floating gate, an injection layer, an active layer, a gate electrode, and a source electrode and a drain electrode, which are provided on the base substrate, in which the source electrode and the drain electrode are opposite to each other and electrically connected to the active layer. The injection layer is provided between the floating gate and the active layer; the active layer is provided between the control gate and the gate electrode; and the floating gate is provided between the control gate and the active layer.