The invention discloses a direct-current argon arc plasma powder spray gun and a manufacturing method and belongs to the field of flame spraying equipment and technology of metal powder and metal ceramic powder.Two novel technologies including a hollow tungsten cathode outer surface annular arcing direct-current plasma heating method and an axial powder feeding mechanism penetrating the core of an argon arc are adopted, and position matching of a negative voltage pressure of the electric arc and the powder feeding mechanism is utilized, so that stability of the spray gun during long-time working is improved, and uniformity in heating temperature of metal powder particles, uniformity in spray speed and stability of spray layer quality are guaranteed.In addition, due to structural changing of a gun body, technology application field of the gun is expanded obviously, and the gun is expected to make a beneficial contribution to development of high technology in the future.