In this study, microstructures of age-hardened 2014 Al alloy forged by cold biaxial alternate forging was investigated by transmission electron microscope. And also, the forming limits of age-hardened 2014 Al alloy were examined using both conventional compression test and biaxial alternate forging. As a result of compression test, it showed a perfect plastic behavior with no visible change in stress after 27% in strain and eventually, the curve fluctuated as a shear crack occurs after 51% strain. However, it was possible to impose very large strains on the 2014-T6 Al alloy workpieces through the biaxial alternate forging of up to 4 passes. The effective strain was possibly accumulated to 356% and 204% as the maximum and average values, respectively. The results of transmission electron microscope indicated that the high density dislocations were distributed after 3 passes. After 4 passes, the distribution of more increased dislocations was observed and band-shaped dislocation clustering appeared.