Embodiments of the present disclosure provide a signal combination circuit, a gate driving unit, a gate driving circuit, and a display device, the signal combination circuit includes a first active level output circuit configured to write an active-level voltage to a driving signal output terminal in a case where a signal provided by a first signal output terminal or a second signal output terminal is at an active level, and a first inactive level output circuit configured to write an inactive-level voltage to the driving signal output terminal in a case where the signals provided by the first signal output terminal and the second signal output terminal are at an inactive level. The signal combination circuit of the embodiments of the disclosure can realize the combination of the single pulse signals output by two shift registers, thereby outputting a double-pulse driving signal.