Objective To establish the inbred strain of the coagulation factor IX knockout mice. Methods\ The mice were bred by brother sister first mating with reproductive performance recorded.The homogeneous mice were selected after F8 Results\ Factor IX knockout mice were developed in the 12th generation.The age of mating was 70-90 day.The average birth litter size was over 5,average weaning litter size was over 3 Conclusion\ The coagulation factor IX knockout mice can be generated steadily.