For the problems of reduced bending fatigue life of free pushing diameter-reducing for tube blanks and axial cracking at the end when the diameter was reduced, the deformation process of the free pushing diameter-reducing was analyzed, and it was revealed that there was a large residual stress in the inner and outer surface layers of the deformed area after the diameter was reduced. Therefore, the three-pass free pushing diameter-reducing process of tube blank was simulated by finite element software ABAQUS, and the distribution laws of the residual stress for the axial, circumferential and radial directions in the deformed area along the length direction and the wall thickness direction were obtained. Furthermore, the influences of friction coefficient, outlet radius of diameter-reducing die, diameter-reducing times and initial wall thickness of tube blank on the residual stress after diameter-reducing were analyzed. Finally, three-pass diameter-reducing tests were carried out on the tube blank, and the geometric parameter changes were measured, and the measured results were in good agreement with the finite element simulation values. It is found that the axial cracking occurs in the third diameter-reducing, which proves that the circumferential residual tensile stress is greater than the strength limit of material.