In this study, effects of Punica granatum seed oil (PGSO) on the immune function of aging model mice induced by D-galactose were determined. The results showed that in the aging model mice, spleen / thymus indexes and ConA-induced spleen/thymus cell proliferation declined significantly. The proportion of splenocytes in division phases also reduced dramatically. PGSO intervention dose-dependently alleviated these immunosuppressive symptoms. In macrophages of aging mice, PGSO enhanced the ability of phagocytosis and producing immunoregulatory factors. Moreover, PGSO increased the content of immunoglobulins and complements in the serum of aging mice. The data above collectively demonstrated that PGSO was capable of improving the immune function in aging model mice. © 2019, Editorial Office of Journal of CIFST. All right reserved.