The application of Aluminum alloy T-stub joints has been found widely in China recently, while the research achievements of the joint are far from adequate for design. This paper is focused on the ultimate load-bearing capacity of aluminum alloy T-stub joints. On the basis of Kulak prying model, formulas for calculating ultimate load-bearing capacity, considering four types of failure modes, are derived. The numerical simulation is carried out by means of ABAQUS FEA. Numerical results are verified by comparing with previous results obtained from experimental analysis. A parametric analysis is performed to investigate the influence of several geometrical parameters on the behavior of aluminum alloy T-stub joints including failure modes, ultimate load-bearing capacity and effective length of flanges. These numerical results are also compared with those calculated by relevant formulas in EC9.