Abstract: Objective: To introduce an exact and sensitive method for screening the methylated patterns of multiple samples and CG sites: Bisulfite Genomic Sequencing (BGS). Methods: Sodiumbisulfite modification of single strand DNA converted unmethylated cytosine to uracil, but 5'methyl cytosine maintained unaltered. This modification created sequence difference between methylated and unmethylated genomic DNA, which can be sensitively detected by PCR. According to this principle, methylated pattern of CG dinucleotide sites of AFP gene promoter in liver cancinoma cells was analyzed. Results: Two abnormal methylations were found in DNA of carcinoma cell by BGS. Conclusion: BGS will be potential in screening the abnormal methylation of gene and will direct a new molecular analysis for genesis of the tumors.