Abstract：Objective：To observe the curative effect of Ziyin Jianghuo tang combined with modern medical therapy for recurrent aphthous ulcer(RAU). Methods：A total of 88 cases of RAU patients were selected as research objects，and were divided into the control group and the treatment group according to the random number table method，with 44 cases in each group. The control group was treated with modern medical therapy，and the treatment group was additionally treated with Ziyin Jianghuo tang based on the treatment of the control group. Both groups were treated for eight weeks. The clinical effects in the two groups were compared；the changes in the total area and number of ulcers before and after treatment in the two groups were compared； the recurrence rates in half a year and one year of follow- up in the two groups were compared. Results： After treatment， the total effective rate of clinical effect was 95.45% in the treatment group and 81.82% in the control group，the difference being significant(P＜0.05). After treatment，the indexes of the area and number of ulcers in the two groups were decreased when compared with those before treatment(P＜0.05)， and the above two indexes in the treatment group were lower than those in the control group， differences being significant(P＜0.05). After treatment， both groups were followed up for half a year and one year； the recurrence rates were 9.09% and 20.45% respectively in the treatment group，and 25.00% and 40.91% respectively in the control group；the recurrence rates in half a year and one year of follow- up in the treatment group were lower than those in the control group， differences being significant(P＜0.05). Conclusion： The therapy of Ziyin Jianghuo tang combined with modern medical therapy has a definite curative effect on RAU， which has more advantages than the single modern medical therapy. It can not only effectively reduce the area and number of ulcers，but also effectively prevent the recurrence of the disease and reduce the recurrence rate.