Objective:To systematically evaluate the clinical efficacy of Baitouweng Decoction combined with mesalazine in the treatment of ulcerative colitis. MethodsDatabases were searched from database creation to December 2017 to collect the randomized controlled trials(RCT) reports about Baitouweng Decoction combined with mesalazine in treating ulcerative colitis which compared with mesalazine. The literature screening,data extraction and quality evaluation were conducted independently by two researchers. The Meta-analysis was conducted by RevMan 5.3 and Stata software.  Results:A total of 12 RCT literatures involving 842 patients were included. The results of Meta-analysis showed that Baitouweng Decoction combined with mesalazine showed better comprehensive efficacy and endoscopic mucosal efficacy compared with mesalazine. It also showed better improvement on symptoms such as abdominal pain and bloody purulent stool. However,no statistically significant difference on improvement of diarrhea was observed(P>0.05).  Conclusion: Compared with mesalazine alone,Baitouweng Decoction combined with mesalazine shows better comprehensive efficacy and endoscopic mucosal efficacy in the treatment of ulcerative colitis,and the improvement effects on abdominal pain and bloody purulent stool are also better than mesalazine alone. However,due to the low quality of the included literatures,the above conclusion needs further verification by high quality studies.