Liposuction on arms and shoulders will make the needle enter liposuction from a hidden position, and the eye of the needle is very small, leaving no scars. Combined with the spiral water knife based on the precise hydrodynamic principle of hydrodynamic fat-dissolving slimming system, the pressurized water accurately acts on the target tissue, selectively separates fat cells, does not harm blood vessels and nerves, and easily solves the problems of arm fat and shoulder hypertrophy.