Objective:To study the characteristics of changes in coagulation indexes after blast injury at high altitude,and to explore its clinical significance.Methods:A total of 13 plateau sheep were selected as the research subjects and numbered according to the random number table method.After collecting the coagulation indicators,the sheep were injured by shell blast to establish the model.Venous blood samples were collected to measure coagulation indexes(PT,APTT,TT,FIB,D-Dimer).Results:1.The PT index at 6-8h after explosion was significantly lower than that before explosion(P<0.05),and the overall trend was first decreased and then increased.(2)The change of APTT index at 24h after explosion was significantly higher than that before explosion(P<0.05),showing a trend of first increasing and then decreasing;(3)The change of FIB index was signifi-cantly higher at 48h after explosion than that before explosion(P<0.01),and was the highest at 72h after explosion(P<0.05),showing an overall upward trend;(4)The change of D-Dimer index at 72 hours after explosion was significantly higher than that before explosion(P<0.05),showing an overall upward trend;(5)The changes of TT index at each time point after the explosion were not statistically significant compared with those before the explosion(P>0.05).Conclusion:The body is in a hypercoagula-ble state after blast injury at high altitude.The dynamic observation of the changes of coagulation indexes can provide certain theoretical basis for the rational use of anticoagulant drugs and the improvement of the prognosis of patients in this area.