Abstract: A patient with hemorrhagic disease was diagnosed as hereditary coagulation factor Ⅶ deficiency by clinical and genetic diagnosis. After the mother of the proband got pregnant, prenatal gene diagnosis was carried out to avoid the fetus bearing the same disease again. Genomic DNA was extracted from peripheral blood of the proband and his family members. All the exons and the flanking sequences of F7 gene were amplified by PCR. PCR products were purified and analyzed by Sanger sequencing. The paternal pathogenic mutation IVS6-1 C＞T and the maternal mutation c.1198 G＞C（p.Val400 Leu） were detected in the peripheral blood samples of the proband. The former leads to the change of classical splicing site in intron 6 of F7 gene and c.1198 G＞C resulted in the change of amino acid sequence at position 400 of F7 gene from Val to Leu. After the proband’s mother was pregnant again, amniotic fluid was aseptically extracted for prenatal diagnosis under the guidance of ultrasound at 18 weeks of gestation. Amniotic fluid DNA was paternally identified by short tandem repeat（STR） to exclude maternal contamination. The same PCR-Sanger sequencing method as the proband was used. It was detected that the fetus carried the maternal F7 gene c.1198 G＞C（p.Val400 Leu） mutation and did not carry the paternal pathogenic mutation IVS6-1 C＞T. The fetus was followed up for 1.5 years after birth, the coagulation function, growth and development were normal.