Objective:To investigate the expression of chemokine MIP-3α and its receptor CCR6 in ulcerative colitis(UC) and to explore its relationship with the involvement and severity of UC,so as to asses their expression in the pathogenesis of UC.Methods:The expression of MIP-3α and CCR6 protein in the colon mucosa was detected by immunohistochemistry method in 35 UC patients and 20 normal controls.Results:MIP-3α and CCR6 were both positive in the UC group and negative or only weakly expressed in the normal control group. The expression of MIP-3α and CCR6 in the UC group was significantly higher than that in normal controls (P<0.01). The expression of MIP-3α and CCR6 was related to the severity and involvement of UC. The expression of MIP-3α was significantly correlated with that of CCR6（r=0.765,P＜0.01).Conclusion: The expression of MIP-3α and CCR6 is positively correlated with each other, and both of them participate in the development and progression of UC. The interaction between the 2 may play an important role in the local damage and pathological changes in UC.