Objective To study of the dynamic role of both positive and negative feedback reactions in blood coagulation.Methods A kinetic model is developed for the reactions of central blood coagulation. Results The system has positive solution only ifβ≥β 0(which exists, but can not be obtained easily by simulation);The concentration of Xa transmits from oscillating slightly to a positive solution to gradually increasing to a positive solution; If κ 3 is over 8 times of its normal level, the system has periodic solution.Conclusion It is evident that Xase must exceed a threshold value to amplify blood coagulation, and the value increases as the concentration of APC increases. Furthermore, after studying the relation of oscillation and periodicity to APC, we found that oscillation may occurs under pathology. In addition, according to mathematics law, we gave the theory base for haemophilia therapy.