Objective To investigate the effect of low dose heparin on blood coagulation and therapeutic outcomes in premature infants with sepsis.Methods Clinical data of 69 septic preterm newborns weighting less than 1 500 g treated in Beijing Obstetrics and Gynecology Hospital were retrospectively analyzed.Among them,29 infants received heparin therapy (6 U/kg,q 8 h,for 3 d,then q12 h,heparin group)and 40 infants did not receive heparin therapy (control group),the coagulation index and therapeutic outcomes were compared between two groups.Results The coagulation indexes PT,TT,APTT and D dimer in heparin group were all significantly lower than those in control group [(15.5±3.5) s vs.(19.0±3.9) s,(15.4±3.5) s vs.(18.8±3.5) s,(47.5±8.6) s vs.(58.4±18.1) s,(1.7±0.8) mg/L vs.(2.6±1.9) mg/L;t=-3.815,4.275,-3.004,-2.459,P＜0.05].The overall clinical effective rate in heparin group was significantly higher than that in control group (86.2％ vs.60.0％,x2 =4.408,P＜0.05).Conclusion Low dose heparin can significantly improve the blood coagulation function and improve the therapeutic effect of premature infants with sepsis.