After solution treatment, the 1420 Al-Li alloy samples were aged at different temperatures in an electric field with different intensity. The measurements made showed that the electric field increased the strength of the 1420 Al-Li alloy, and best properties were obtained when they were aged at 120 ℃ with E=4 kV/cm for 12 hrs. The electric field promoted the nucleation of δ′ phase, increased the quantity of the δ′ phase, and made the size of the δ′ phase particles smaller. The electric field restrained the formation and growth of PFZ, and increased the intensity of the electric field while the width of the PFZ was decreased. After solution treatment, the 1420 Al-Li alloy samples were aged at different temperatures in an electric field with different intensity. The measurements made the the electric field increased the strength of the 1420 Al-Li alloy, and best properties were obtained when they were aged at 120 ° C with E =  4 kV / cm for 12 hrs. The electric field promoted the nucleation of δ’ phase, increased the quantity of the δ ’phase, and made the size of theδ ’Ƒ phase particles smaller. The electric field restrained the formation and growth of PFZ, and increased the intensity of the electric field while the width of the PFZ was decreased.