Abstract: ObjectiveTo investigate the clinical significance and abnormal expression of the Cyclin B1 and CDK1 in different colorectal cancer tissues. MethodsThe expression of Cyclin B1 and CDK1 was examined by immunohistochemistry method in normal colorectal tissues(11cases), colorectal cancer tissues(28 cases) and adjacent tissues(27cases). ResultsThe positive expression rates of Cyclin B1 and CDK1 were 9.1%(1/11) and 18.2%(2/11) in normal colorectal tissues, 89.3%(25/28) and 92.9%(26/28) in colorectal cancer tissues, and 25.9%(7/27) and 33.3%(9/27) in adjacent tissues, respectively, the positive expression rates of Cyclin B1 and CDK1 had statistical significance in different groups(P<0.05). There was no statistical significance of Cyclin B1 and CDK1 positive expression rates in different differentiation degree of colorectal cancer(P>0.05). ConclusionOverexpression of Cyclin B1 and CDK1 are detected in different differentiation degree of colorectal cancer, it's also in adjacent tissues. Maybe, there is an important regulatory effect on the process of the colorectal cancer development.