Objective To identify the factor Ⅻ gene mutations in two Chinese pedigrees with congenital factor Ⅻ deficiency. Methods The peripheral blood samples were collected from the probands and their family members, and the plasma FⅫ∶C were determined. All the exons and exon1,intron boundries of the FⅫ gene were amplified with PCR and sequenced thereafter. Results An insertion mutation C in 7142 and two missense mutations Gly526Asp and Gly542Ser were disclosed in the two pedigrees. All the mutations existed in a heterozygous state. Conclusions The insertion mutation C in 7142 and the mutations Gly526Asp and Gly542Ser attribute to the pathogenesis of the congenital factor Ⅻ deficiency in Chinese.