A fixing device for repairing an aluminum alloy wheel hub includes a base and universal wheels connected with the bottom of the base through support legs, wherein one side of the bottom plate is connected with air cylinders; the top of the bottom plate is connected with a fixing plate through a rotating shaft mounted rotationally; corresponding sides of vertical plates at the two sides of the fixing plate are each connected with a pressing plate through two sets of springs; adjusting bolts penetrate through the middles of the vertical plates; a first groove is formed in the middle of the fixing plate; two sets of guide rollers are rotationally mounted in the first groove; a top plate is fixedly mounted at the top of the bracket; a push plate is connected with the bottom of the top plate through a second hydraulic cylinder.