Abstract： Objective The purpose is to analyze the effect of low molecular weight heparin sodium injection combined with conventional physical therapy on coagulation function and hemorheological indicators in postoperative patients with lower limb fractures.Methods This study used 80 patients with lower limb fractures admitted to Guixi People's Hospital from January 2021 to January 2023.They were randomly divided into an observation group(40 cases)and a control group(40 cases)using a random number table method.Both groups of patients underwent routine examinations and received basic treatment after admission.The control group received routine rehabilitation therapy.On the basis of the control group,the observation group received low molecular weight heparin sodium injection combined with routine physical therapy,both groups of patients continued treatment for 2 weeks.Observe and compare the coagulation function[prothrombin time(PT),prothrombin time(APTT),and D-dimer(D-D)levels],hemorheology(plasma viscosity,high shear whole blood viscosity,and low shear whole blood viscosity),lower limb venous thrombosis,and incidence of adverse reactions between two groups of patients.Results After 2 weeks of continuous treatment,the PT(15.74±2.32)s and APTT(29.76±3.82)s levels in the observation group were higher than those in the control group(13.90±1.98)s and(26.85±3.46)s,and the D-D(175.67±29.88)g/L levels were lower than those in the control group(251.43±33.47)g/L;the high shear whole blood viscosity(3.98±0.24)mPs.s,low shear whole blood viscosity(8.23±0.14)mPs.s,and plasma viscosity(1.38±0.42)mPs.s were lower than those of the control group(4.44±0.38)mPs.s,(9.59±0.28)mPs.s,and(1.60±0.47)mPs.s,with statistically significant differences(P＜0.05).There was no statistically significant difference in the incidence of lower limb venous thrombosis between the two groups(P＞0.05).Conclusion Low molecular weight heparin sodium injection combined with conventional physical therapy has a significant effect on the treatment of postoperative patients with lower limb fractures.It can effectively improve the coagulation function and hemorheological indicators of patients,effectively prevent the incidence of lower limb venous thrombosis,and has high safety.It has good application value.