Abstract: Objective To observe the CpG island methylation status, mRNA and protein expression of the Wnt inhibitory factor-1 (Wif-1) gene with procaine or 5'-Aza-2'-deoxycycytidine (5-aza-dc) on HepG₂. And to explore the comparison of the demethylation with 5-aza-dc or procaine. Methods HepG₂ cells were treated with 5-aza-dc or procaine. Wif-1 mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR). Wif-1 protein expression was detected by Western blot. The promoter methylation status of Wif-1 gene on treatment or not were detected by methylation-specific PCR (MSP). Results ① RT-PCR and Western blot exhibited that both Wif-1 mRNA and Wif-1 protein expression were positive in groups treated with procaine and 5-aza-dc and highly positive in the L₀ cells group, but weakly even negative in the HepG₂ cells without any treatment, the difference were statistically significant (P<0.05) (procaine experimental group was higher than that of 5-aza-dc experimental group, P<0.05). ② The positive rates of the promoter hypermethylated in procaine and 5-aza-dc groups were (14.41±3.37)% and (29.29±1.84)%. Both of the two groups showed a part of the de-methylation status (P<0.05). Conclusion Both of procaine and 5-aza-dc can reverse the abnormal methylation of Wif-1 gene. Procaine can be more effective than conventional used 5-aza-dc and could be a new demethylation drug.