The invention discloses an aluminum 
alloy workpiece additive manufacturing method implemented through 
friction stir welding. On the basis of an existing 
electric arc additive manufacturing aluminum 
alloy workpiece, the characteristic that aluminum 
alloy is soft in property is combined, after an aluminum alloy workpiece is manufactured from 
electric arc additives layer by layer, 
friction stir welding intensification treatment is conducted on each layer, and therefore, defects such as pass gaps, interlayer incomplete fusion, air holes and the like can be eliminated through friction stir weldingwhen each layer is manufactured. Compared with the pure 
electric arc additive manufacturing aluminum alloy workpiece, by means of the method, the structural state of the aluminum alloy workpiece obtained through additive manufacturing can be improved; the grains can be finer; second-phase grains are finer and are distributed more uniformly; and the 
dislocation density achieved in the aluminum alloy additive manufacturing workpiece is increased. Compared with existing 
friction stir welding intensification, grain refining and defect 
elimination are conducted on each layer of the workpiece so that the strength of the whole workpiece can be improved rather than only 
surface modification, namely surface intensification, is conducted.