In this work, the hydraulic bursting method was used to investigate the bursting failure of aluminum alloy as-formed T-shaped tube by hydroforming, which consisted of the rupture region and bursting pressure. The bursting pressure was calculated by theoretical formula and two finite element models of T-shaped tubes with uniform thickness and hydroforming thickness were established. The hydraulic bursting failure simulation and experiment was carried out. In the simulation results, the failure directions of T-shaped tubes with uniform thickness were along the circumferential direction, while the failure directions of T-shaped tubes with hydroforming thickness were along axis of the main tube. Through stress analysis, the allowable circumferential film stress was about 1/2 of the allowable axial film stress, which indicated that the rupture failure should be along axis of the main tube. The failure location appeared at the shoulder. The fractured morphology was observed by scanning electron microscopy (SEM). A large number of equiaxed dimples and secondary phase particles appeared in the failure location. The experimental results were consistent with the simulation results of the as-formed T-shaped tube by hydroforming. Finally, the accuracy of the bursting pressure formula was evaluated according to the experimental results.