Al2Cu (θ) phase is the main and the most important intermetallic compound in AA 2219 aluminum alloy, which is widely used in the aerospace industry. Added alloying elements (Mn, Ti and Zr) as well as impurity elements (Fe and Si) in 2219 aluminum alloy always exist in the θ phase. First-principles calculations based on Density Functional Theory (DFT) were used to theoretically investigate the influence of doping Fe, Si, Mn, Ti and Zr on the structure and stability of the doped θ phases. Based on the preferential site occupation of each doping element, it was found that the doped θ phases behave differently in structural stability, crystal structures, bulk modulus as well as electronic structures. The results of this study could provide theoretical foundation and guidance for a better understanding of this strengthening phase.