Abstract：Objective：To observe the clinical effect of Kangfuxin Liquid in adjuvant therapy of oral ulcer in children and its effect on immune function. Methods：A total of 105 cases of children with oral ulcer were selected for retrospective analysis and divided into the control group and the observation group according to different treatment methods， with 53 and 52 cases in each group respectively. The control group was treated with routine treatment， sprays for stomatitis， and compound vitamin B tablets. The observation group was additionally treated with the oral administration with Kangfuxin Liquid based on the treatment of the control group. Clinical effects，the time of symptom improvement，adverse reactions and recurrence were compared between the two groups. The changes in traditional Chinese medicine(TCM) syndrome scores，ulcer area，congestion degree，scores of Visual Analog Score(VAS) for pain and immune function before and after treatment were compared between the two groups. Results： In the observation group， the total effective rate was 92.30% and the recurrence rate was 2.08% ； in the control group， the total effective rate was 83.01% and the recurrence rate was 13.64% ， differences being significant(P＜0.05). Before treatment， there was no significant difference being found in the comparison of TCM syndrome scores of bad breath，pain in mouth，thirst，yellow-coloured urine and costipation，and red tongue and yellow coating between the two groups(P＞0.05). After treatment，each TCM syndrome score in the two groups was decreased(P＜0.05)，and the score in the observation group was lower than that in the control group(P＜0.05). After treatment， the remission time of ulcer pain， the healing time of ulcer， and the improvement time of appetite in the observation group were shorter than those in the control group，the difference being significant(P＜0.05). Before treatment，there was no significant difference being found in the comparison of ulcer area，congestion degree and VAS scores between the two groups(P＞0.05)；after treatment， the above indexes in the two groups were decreased when compared with those before treatment(P＜0.05)，and each index in the observation group was lower than that in the control group(P＜ 0.05). Before treatment， there was no significant difference being found in the comparison of levels of CD3＋，CD4＋，CD8＋，and CD4+/CD8+ between the two groups(P＞0.05). After treatment，CD3＋，CD4＋， and CD4 +/CD8 + in the two groups were increased when compared with those before treatment(P＜0.05)， and CD8＋ was decreased(P＜0.05)；the improvement of above indexes in the observation group was more significant than that in the control group(P＜0.05). The incidence of adverse reactions was 5.76% in the observation group， and 18.86% in the control group， the difference being significant(P＜0.05). Conclusion： Kangfuxin Liquid in adjuvant therapy of oral ulcer in children can enhance the curative effect and immune function， reduce the incidence of adverse reactions， and effectively improve clinical symptoms，with high safety.