Microstructural evolution and mechanical properties of Al-4.11 wt% Cu alloys subjected to multi-axial compression (MAC) and subsequent annealing were investigated. To clarify the influence of precipitated phases on mechanical properties, special samples containing only one kind of precipitated phase were prepared. During MAC at room temperature, θ"-phase-contained and θ′-phase-contained samples simultaneously showed increased strength and ductility as a function of MAC passes. This was ascribed to the considerable dissolution of precipitated phases induced by MAC that formed a supersaturated solid solution. In subsequent annealing at 393 K for 1 h, new precipitated phases appeared and the strength and ductility of deformed samples increased as precipitation proceeded. Additionally, transmission electron microscopy indicated that the MAC process accelerated the phase precipitations. Annealed mechanical properties were a function of MAC passes, annealing time, and temperature. In this study, an optimum comprehensive mechanical property was achieved in the θ"-phase-contained specimen, after eight passes of MAC and 1 h annealing at 393 K.