Objective:To investigate the expression of miR-451 and MIF in colorectal cancer and colorectal adenoma and their correlation with clinicopathologic features in colorectal cancer. Methods:Real time polymerase chain reaction(RT-PCR) was performed to examine the expression level of miR-451 in 25 cases of colorectal cancer and matched non tumor adjacent tissue and 10 cases of colorectal adenoma tissue specimens. MIF protein was detected by immunohistochemistry(SP method). The relationships among the expression of miR-451, MIF and the clinicopathologic features of colorectal cancer were analyzed. Results:The expression level of miR-451 was significantly lower in the tumor tissues and adenoma tissues than that in the adjacent tissues (P < 0.01,P < 0.05). There were 6 cases up-regulated and 19 cases down-regulated in colorectal cancer,and the down-regulated rate was 76% (19/25). There were 3 cases up-regulated and 7 cases down-regulated in colorectal adenoma,and the down-regulated rate was 70% (7/10). The positive rate of MIF in colorectal cancer was 72%,the positive rate was 50% in colorectal adenoma and the positive rate was 32% in adjacent tissues. Down-regulated miR-451 expression and up-regulated MIF were associated with the cell differentiation (P < 0.05) in colorectal cancer patients. No significant association was found between the expression of miR-451 and MIF with the status of age,gender,Dukes staging system histological type, depth of tumor invasion and lymphatic metastasis. Conclusion:Up-regulated miR-451 expression may inhibit MIF expression,and then control colorectal carcinogenesis and the development process.