This paper describes a novel rapid manufacturing and remanufacturing system based on robotic gas metal arc welding. If worn parts are maintainable, this system play a repairer role; if worn parts are unfit to remain in service, this system play a manufacturer role. This system works in ‘modeling - slicing - stacking’ principle. First, Detecting and building three-dimensional models of damaged zone by structured light. Second, Slicing established three-dimensional model in layers with some thickness. Third, planning robotic tool path to get optimumwelding path and parameters. Finally, executing remanufacturing task with robotic GMAW stacking layer by layer. This system remanufactures parts in human - robot interactive way. Take a half cylinder shell as worn part, experiments are conducted. Results show the mean error of surface smoothness is less than 0.5mm.