Objective:To explore whether aberrant methylation is a inhibition factor to transcriptional inactivation of SOX7 in cancer cell lines by investigation of the expression and methylation status of SOX7 gene in human pancreatic cancer cell lines. Methods:RT-PCR method was used to explore mRNA expression of the SOX7gene. Bisulfite sequencing PCR(BSP) and combined bisulfite restriction analysis(COBRA) were used to test promoter methylation of SOX7 gene in BXPC-3,CFPAC-1,PANC-1 and SW1990. Re-testing of these two indicators after the treatment of 5-aza-2-deoxycytidine(5-aza-dC). Results:SOX7 gene was obviously expressed in BXPC-3 and CFPAC-1 but silenced in PANC-1 and SW1990. The rate of methylation of CpG island of SOX7 in PANC-1 and SW1990 was much higher than the other two genes. After the treatment of 5-aza-dC in hypermethylation cell line PANC-1 and SW1990,the methylation rate of SOX7 gene promoter was decreased and the mRNA of SOX7 was re-expressed. Conclusion:This promoter hypemlethylation is correlated with SOX7 gene expression in pancreatic cancer cell line PANC-1 and SW1990 and plays a key role in SOX7 silencing.