Objective: To investigate the immune enhancement effect of red ginseng aqueous extract in mice. Methods: The aqueous extract of red ginseng was obtained by water extraction and concentration, and the aqueous extract 10 ml was equivalent to raw material 2.86 g. The experiment was divided into the blank control group, low dose group of red ginseng aqueous extract 0.24 g/(kg•d), middle dose group 0.48 g/(kg•d) and high dose group 1.43 g/(kg•d). In order to explore the immunoregulation effect of red ginseng aqueous extract, Organ/body weight ratio measurement, the delayed type hypersensitivity (DTH) reaction, the spleen lymphocyte transformation experiment induced by Con A, the detection of antibody-producing, the determination of serum hemolysin experiments, the clearance rate of carbon particles, the phagocytosis effect of macrophages with chicken red blood cell experiments, and the determination of natural killer cell activity were carried out with the mice. Results: Compared to the blank control group, the tow edema degree (0.62 ± 0.14 mm, 0.53 ± 0.12 mm vs. 0.36 ± 0.10 mm) of low dose group and medium dose group significantly increased (P<0.05). The ability of proliferation of T lymphocytes (0.173 ± 0.054, 0.189 ± 0.063 vs. 0.098 ± 0.012) of low dose group and high dose group significantly increased (P<0.05). The number of haemolytic empty spots (137.49×10³ ± 24.73×10³, 148.43×10³ ± 27.53×10³ vs. 112.96×10³ ± 26.28×10³) of medium dose group and high dose group significantly increased (P<0.05). The phagocytosis rate (35.67% ± 3.82%, 49.26% ± 6.54%, 57.92% ± 7.36% vs. 24.34% ± 4.22%) and index (0.72 ± 0.23, 0.82 ± 0.15, 0.91 ± 0.26 vs. 0.35 ± 0.11) of low-, medium-, high-dose group significantly increased (P<0.05). However, there was no statistical difference in the organ/body weight ratio of the experimental animals, the determination of serum hemolysin experiments, the clearance rate of carbon particles, and NK cells activity. Conclusion Red ginseng aqueous extract has an exact role in immunity improvement in mice.