Abstract: Objective：To determine expression levels of deathassociated protein kinase (DAPK) gene and analyze the methylation status of DAPK promoter in human fetal mesenchymal stem cells (FMSC) and its mutant F6 tumor cells. Methods：The expression of DAPK gene was detected by RT-PCR. The methylation ofDAPK promoter was detected by methylation specific PCR (MS-PCR). The products of methylation were confirmed by sequencing. Results：DAPK was expressed in FMSC, but not in F6 cells. The promoter of DAPK gene was methylated in F6 cell line and partially methylated in FMSC. Conclusion：The methylation of promoter may be an important mechanism leading to downregulation of DAPK gene expression in F6 cells, which plays an important role in the mutation of FMSC and the transformation of FMSC into F6 tumor.