Objective:To observe the effects of Danshen Injection combined with mesalazine on the serum levels of hypoxia inducible factor -1α(HIF-1α) and inflammatory cytokines such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6) and IL-10 in patients with mild to moderate active ulcerative colitis(UC). Methods78 patients with mild to moderate active UC were randomly divided into the control group and treatment group,39 cases in each group. The control group was treated with mesalazine,and the treatment group was treated with Danshen Injection based on the treatment for the control group,with a course of 2 weeks. The clinical efficacy was observed. The changes on clinical symptom scores,serum levels of HIF-1α,cyclooxygenase-2(COX-2)and inflammatory cytokines,Sutherland disease activity index(DAI) score and endoscopic mucosal score were compared.  Results:①The total effective rates were 92.31% in the treatment group and 74.36% in the control group,and the clinical efficacy of the treatment group was better than that of the control group(P<0.05). ②After treatment,the scores of diarrhea,pus and blood stool,abdominal pain and abdominal distension in the treatment group were lower than those in the control group(P<0.01). ③After treatment,the DAI score and endoscopic mucosal score in the treatment group were lower than those in the control group(P<0.05). ④After treatment,the serum levels of HIF-1α,COX-2,TNF-α and IL-6 in the treatment group were lower than those in the control group(P<0.05),and the IL-10 level in the treatment group was higher than that in the control group(P<0.05).  Conclusion:Danshen Injection combined with mesalazine shows satisfactory efficacy in treatment of mild to moderate active ulcerative colitis,compared with mesalazine alone,it can better relieve the clinical symptoms of patients,promote the intestinal mucosal repair and enhance the clinical efficacy. Its mechanism may be associated with down-regulating HIF-1α expression and up-regulating IL-10 expression.