Objective To study the treatment of oral ulcer powder Cimicifuga experimental oral ulcer in rats and its partly mechanisms of synergistic effect. Methods The rats were divided into blank group， oral ulcer film group， ulcer powder group， ulcer powder combined+cohosh group. Those groups were established by film NaOH crystal chemical cauterization except the blank group. Then HE method for oral mucosal tissue staining to observe the pathological changes， the detection area rats of group size， healing rate changes， ELISA method to detect the changes of IFN-γ and IL-6 detection. Western-blot method to detect the expression of MMP-2， 9. Results After modeling， ulcer in the rats of model group was round or oval， the surrounding tissue swelling； the ulcer area was gradually reduced after administration. In the ulcer area， IFN-γ， the levels of IL-6 and MMP-2， 9 expression levels， the oral ulcers scattered combined with cohosh group were significantly lower than the single drug group. Conclusion Oral ulcer powder combined with Rhizoma Cimicifugae synergy in treatment of oralulcer， and its mechanism may release and inhibition of inflammatory mediators and down regulated the expression of MMP-2， 9.