Abstract: According to a new processing technology and bulging device for driving axle housing integral compound bulging, the load requirement of tube blank deformation is introduced, and the operation procedure of replacing the central hydraulic cylinder twice for tube blank deformation is analyzed in detail. Then, combined with the functional requirements of bulging deformation, a compound bulging hydraulic system is designed by using reasonable hydraulic loops such as speed regulation, pressure regulation, synchronization, balance, buffer and direction control. The system features low energy consumption, less heat generation, small impact, good stability and high motion accuracy. The operation of system is the combined action of left and right horizontal cylinders and central hydraulic cylinder Ⅰ, Ⅱ and Ⅲ, the nine-bar linkage mechanism performs compound linkage. Then combined with outer mold constraints, the first, second and third bulging deformation of the heating slotted tube blank was carried out, and the semi-finished driving axle housing was obtained.