Abstract: In order to investigate the effect of electric field on point defects, an external electric field was applied to GH4169 superalloy during aging at different temperatures. The results indicated that the energy provided by thermal aging at 500°C without electric field is not enough to promote the atoms jump out of the normal lattice position and form new monovacancies, but it can promote the atoms at lattice distortion position and adjacent to vacancy to jump again. The gradient force has been produced on uncharged atoms by intense electric field applied, which can enhance atomic thermal vibration. The average positron annihilation lifetime increases by 6%~7% when the alloy aged at 600, 700 and 800°C with 8kV/cm intense electric field, leading to the increasing of average size of vacancy in the alloy.