Terahertz quantum cascade laser (THz QCL) is a kind of compact and coherent solid continuous wave source with important potential applications, and it is one of the international research hotspots. At present, the research on array coupling is particularly important since it is an effective solution to the problems and difficulties in further increasing output power for THz QCLs. The current structures of THz QCL array coupling are summarized and analyzed. The research status and possible future development directions of THz QCL array are summarized and discussed.