Objective:To identify gene mutations of a patient with coagulation factor Ⅹ(FⅩ) deficiency. Methods:The activated partial thromboplastin time(APTT), prothrombin time(PT), thrombin time, the activities of FⅡ,FV-FⅦ,FⅧ,FⅨ and FⅩ(FⅡ:C,FⅦ:C,FⅧ:C,FⅨ:C and FⅩ:C) were performed for phenotypic diagnosis. The genomic DNA was extracted from the peripheral blood of the proband and all the 8 exons and their flanks of F10 gene were amplified by polymerase chain reaction(PCR). The PCR products were screeed by direct sequencing and the mutations were further confirmed by restricted enzyme digestion to eliminate the possibility of polymorphism. Results:APTT,PT,TT,FⅡ:C,FⅤ:C,FⅦ:C,FⅧ:C,FⅨ:C and FⅩ:C of the proband were 100 s, 46.6s,13.9 s,60.0%,89%,59%,81.5%,63% and 2.4%, respectively. Compound heterozygous missense mutations in F10 gene were identified in the proband. One was G to A in exon 2, leading Gla(GAG) 26 to Lys(AAG) in the Gla domain; another was T to C in exon 8, resulting the substitution of Ser(UCC)425 by Pro(CCC) in the catalytic domain. Conclusion:These two de novel heterozygous missense mutations might be the molecular mechanisms of coagulation factor Ⅹ deficiency for the patient.