Coaxial powder feeding nozzle, as one of key components in laser metal additive manufacturing system equipment, directly affects the forming accuracy and performance of parts. Because of its importance, a variety of new powder delivery nozzles have been developed by scholars at home and abroad. In this paper, the research on coaxial powder feeding nozzles is briefly summarized from two different powder feeding methods of "powder feeding by light outside" and "powder feeding by light inside", whether the laser beam and powder beam can vary focal length or not is analyzed, the characteristics of coaxial powder feeding nozzles are pointed out, and the development of the coaxial powder feeding nozzles in the future is provided.