Abstract: 　Objective　To detect the 5′CpG island methylation of APC( adenomatous polyposis coli) gene promoter region in cervical carcinoma cell lines (HeLa,CaSki,SiHa), and to investigate the possibility of Hydralazine in restoring the expression of APC gene through demethylation. Methods　The CpG island methylation status of APC gene promoter region of the cervical carcinoma cell lines were analyzed using methylated specific polymerase chain reaction (MSP). The mRNA expression profile of APC gene was analyzed by using RT-PCR after Hydralazine treatment. Results　 The CpG island of APC gene was methylated in HeLa and hemimethylated in CaSki but not in SiHa. The mRNA expression of APC gene can be detected after a certain concentration Hydralazine treatment. Conclusion The APC gene non-expression in cervical carcinoma is associated with CpG island methylation in APC gene promoter region. Hydralazine, served as a demethylating agent, enables to restore the expression of APC gene.