Synchronous powder-feeding space laser machining and three-dimensional forming method and device

A synchronous powder-feeding space laser machining and three-dimensional forming method and device, the method comprising: dividing a three-dimensional solid into a plurality of forming units according to a form simplification and nozzle cladding scanning accessibility principle, and dividing each forming unit into a plurality of laminates; employing a single-beam gas-carried powder-feeding mode in a hollow annular laser; controlling a mechanical arm (7) to drive an in-laser powder-feeding nozzle (1) to move and scan along a predetermined trajectory in a filling area and a boundary area of the laminate; and sequentially conducting cladding and stacking formation of the laminate for the entire unit. The device comprises the in-laser powder-feeding nozzle (1), a laser generator (6), the mechanical arm (7), a control module (4), a transmission optical fiber (5), a gas-carried powder feeder (3) and a gas source (2); the control module (4) is connected to the mechanical arm (7), the laser generator (6) and the gas-carried powder feeder (3) respectively; and the in-laser powder feeding nozzle (1) is fixed at the front end of the mechanical arm (7) and can move in space together with the mechanical arm. The method can conduct cladding machining and three-dimensional stacking formation in space on any surface, and realizes supportless three-dimensional forming of parts with complex structures such as a hanging structure and a cavity.