OBJECTIVE： To systematically review the efficacy of ursodeoxycholic acid （UDCA） in the prevention ofulcerative colitisassociated colorectal cancer （UC-CRC） and dysplasia （UC-Dys）， and provide evidence-based reference for clinic. METHODS： Retrieved from Cochrane Library， EMBase， PubMed， CJFD， CBM， VIP and Wanfang Database， randomized controlled trials （RCT） or cohort studies about UDCA （test group） versus placebo （control group） in the prevention of UC-CRC and UC-Dys were collected. Meta-analysis was performed by using Rev Man 5.3 software after quality evaluation and data extraction by Cochrane Manual 5.1.0. RESULTS： Totally 7 studies （3 randomized controlled trials and 4 cohort studies） were included in the analysis， involving 672 patients. Results of Meta-analysis of 3 RCT showed that there was no significant difference in the incidence of UC-CRC and UC-Dys between 2 groups [OR＝0.95，95％CI（0.17，5.12），P＝0.95]； results of Meta-analysis of 4 cohort studiesshowed that there was no significant difference in the incidence of UC-CRC and UC-Dys between 2 groups[OR＝0.74，95％CI（0.30， 1.84），P＝0.52]. Results of subgroup analysis showed， the incidence of UC-CRC and UC-Dys in test group with low-dose UDCA（＜15 mg/kg） was significantly lower than control group， the difference was statistically significant [OR＝0.19， 95％CI（0.08， 0.49），P＜0.001]； there were no signifficant diferences in the incidence of UC-CRC and UC-Dys in high-dose UDCA group[OR＝1.97，95％Cl（0.53，7.25），P＝0.31]（≥15 mg/kg）. There was no significant difference in the incidence of adverse reactions（P＞0.05）. CONCLUSIONS： UDCA can not decease the incidence of UC-CRC and UC-Dys， it only prompts a possible trend toward decreased UC-CRC and UC-Dys risk in low-doseUDCA.