The invention discloses a method for manufacturing a car axle case, which comprises the following steps of: A, blanking and making a flitch; B, downwardly punching the middle part of the flitch obtained in the step A; C, extruding two sides of the flitch by a hydraulic machine to upwardly bend the flitch; D, inwardly bending the end part of the upwardly bent flitch, and aligning two end parts of the bent flitch to each other; E, after aligning the two ends of the flitch to each other, cutting surplus burrs on the end parts of the flitch, and welding; F, mounting and welding spindle noses, and welding seal edges and plate spring frames; and G, obtaining the car axle case as a finished product. The method has the advantages of low manufacturing cost, simple manufacturing technology, once molding of product, few welding seams, high strength and rigidity of product, high qualification rate and small labor intensity of workers.