Abstract：Objective：To observe the clinical effect of Zhizi Jinhua pills assisting western medicine for recurrent oral ulcer and its effects on immune function. Methods： A total of 98 cases of patients with recurrent oral ulcer were selected retrospectively and divided into the control group and the observation group according to different treatment methods in data， with 49 cases in each group. The control group was given the oral administration of dexamethasone tablets， vitamin B complex tablets and vitamin C tablets，and the observation group was additionally treated with Zhizi Jinhua pills based on the treatment of the control group. Clinical effects in the two groups were evaluated. Chinese medicine syndrome scores， Visual Analogue Scale(VAS) for pain and immune function before and after treatment as well as the ulcer pain relief time，ulcer healing time，adverse reactions and recurrence rates were compared between the two groups. Results： The total effective rate was 89.80% in the observation group， higher than that of 79.59% in the control group，the difference being significant(P＜0.05). After treatment，the scores of each syndrome in the two groups were decreased， and the scores in the observation group were lower than those in the control group(P＜0.05). The ulcer pain relief time and ulcer healing time in the observation group were shorter than those in the control group， the difference being significant(P＜0.05). After treatment， CD3+，CD4+，and NK in the two groups were increased when compared with those before treatment，and CD8+ were decreased(P＜0.05)；CD3+，CD4+，and NK in the observation group were higher than those in the control group， and CD8 + was lower(P＜0.05). After treatment， VAS scores in the two groups were decreased when compared with those before treatment，and the score in the observation group was lower than that in the control group(P＜0.05). The incidence of adverse reactions was 6.12% in the observation group， lower than that of 18.37% in the control group， the difference being significant(P＜0.05). The recurrence rates in the observation group after six months and one year of treatment were lower than those in the control group(P＜0.05). Conclusion： Zhizi Jinhua pills assisting western medicine for recurrent oral ulcer can enhance clinical effect， reduce Chinese medicine syndrome scores and adverse reactions， shorten ulcer healing time， relieve pain， and improve immune function， with high safety and low recurrence rate.