The invention discloses an overall thermal expansion manufacturing method for a heavy-duty car drive axle housing, and overcomes the problems that currently, material utilization rate is low, machinery processing load is heavy, the punching and welding production process chain is long, welding workload is heavy, product rigidity is low, and service life is short. The method includes 1, determining the structural size of a used billet, namely selecting the appropriate expansion ratio according to geometrical features and size parameters of an axle housing to be processed, determining the diameter of the specification of the billet to be D0, the wall thickness to be H0 and the length to be L0; 2, preforming the billet before thermal expansion; 3, cutting prefabricated hole in the middle of the preformed billet, namely cutting axial elongated prefabricated through holes in the bedding face after the middle of the billet is flattened and allowing an upper prefabricated through hole and a lower prefabricated through hole to be centered; 4, preforming in the manner of thermal expansion; 5, forming in the manner of thermal expansion; 6, shaping, namely eliminating drive axle housing lute holes and unrounded degree of a lateral flange after twice thermal expansions and allowing the radius of the large arc of an axle housing transition area to be 200mm.