Abstract：Objective：To observe the clinical effect of modified Hewei Huashi Decoction combined with folic acid for chronic atrophic gastritis of spleen deficiency and dampness obstruction type and its effect on gastric function and immune function. Methods： A total of 82 cases of patients with chronic atrophic gastritis of spleen deficiency and dampness obstruction type were divided into the treatment group and the control group according to the random number table method，with 41 cases in each group. The control group was treated with folic acid tablets，and the treatment group was additionally treated with modified Hewei Huashi Decoction based on the treatment of the control group. Traditional Chinese medicine (TCM) syndrome scores，and the levels of gastrin-17 (G-17)，pepsinogen (PG)Ⅰ，PGⅡ，and PGⅠ/PGⅡ ratio (PGR) in serum，and T lymphocyte subsets (CD4+ ，CD8 + ，and CD4 + /CD8 + ) in peripheral blood were compared between the two groups before and after treatment. Clinical effects and the safety in the two groups were evaluated. Results：The total effective rate was 87.80% in the treatment group，higher than that of 68.29% in the control group (P＜0.05). After treatment，the levels of G-17，PGⅠ，and PGR in serum，and CD4+and CD4+ /CD8 + in peripheral blood in the two groups were increased when compared with those before treatment (P＜0.05)，and the above indexes in the treatment group were higher than those in the control group (P＜0.05). After treatment，TCM syndrome scores (main symptom，secondary symptom，and the total scores)，and the levels of PGⅡ in serum and CD8 + in peripheral blood in the two groups were decreased when compared with those before treatment (P＜0.05)，and the above indexes in the treatment group were lower than those in the control group (P＜0.05). No adverse responses happened in the two groups. Conclusion：Modified Hewei Huashi Decoction combined with folic acid has a definite curative effect in the treatment of chronic atrophic gastritis of spleen deficiency and dampness obstruction type and can improve gastric function and immune function of patients，with a relatively high safety.