Objective：To explore the influences of hydroquinone（HQ） on methylation level of WRN gene and expression of DNMT1 gene in K562 cells. Methods：The low dose HQ group，middle dose HQ group andhigh dose HQ group were treated with 15 μmol/L，30 μmol/L，60 μmol/L hydroquinone for 72h at intervals and repeatedly，while the blank control group cells were cultured with PBS. The survival rate of each experimental group was detected by MTT assay. The methylation level of WRN gene was detected by bisulfite sequencing PCR（BSP）. The protein expression of DNMT1 gene was detected by Western blot. The mRNA expressions of DNMT1 gene were detected by real-time fluorescence quantitative PCR. Results：①The results of MTT showed that the cell viability decreased with the increasing of HQ concentration（P=0.000）. ②Compared with the that of control group，the difference of the methylation rates of low dose HQ group，middle dose HQ group，high dose HQ group，was statistically significant（ χ2=7.50，P=0.048）. ③Compared with that of the control group，the relative expression of mRNA and protein of DNMT1 of each HQ group decreased（P=0.000）. Conclusion：HQ can increase the methylation level of WRN gene and down-regulated the expression of DNMT1 gene in K562 cells.