objective:to explore the significance of matrix metalloproteinase 2(mmp2) gene in colorectal cancer with liver metastasis. Methods:during operation,the fresh specimens of primary cancer lesions,surrounding normal colorectal mucosas,hepatic metastases and surrounding normal liver tissues were collected in 21 patients who suffered from colorectal cancer with liver metastasis. The mrna and protein expression of mmp2 among these specimens were detected by sybr green real－time rt－pcr and western blot method. Results:there were significant differences of mrna expression level in these specimens among 21 cases,which was highest in hepatic metastases and lowest in surrounding normal colorectal mucosas. The protein expression in most of cases (18/21) were lower in surrounding normal colorectal mucosas than other specimens by western blot. There was no difference between primary cancer lesions and hepatic metastases,and both of them were higher than surrounding normal liver tissues among all cases. Conclusion:the overexpression of mmp2 gene in primary cancer lesions and hepatic metastases were beneficial for degrading the extracellular matrix. It might be one of molecular mechanisms in colorectal cancer liver metastasis that the expression of mmp2 mrna in hepatic metastases was higher than that of primary cancer lesions due to the up－regulation of mmp2 gene. The overexpression of mmp2 in normal liver tissues surrounding hepatic metastases might be correlated with the regeneration of hepatic metastasis.