Objective：To observe the clinical effect of Xiangdan injection combined with low molecular dextranonincrease of umbilical artery blood flow resistance in late pregnancy.Methods：Selected 88 cases of pregnant women with increased umbilical artery blood flow resistance in late pregnancy and divided them into the treatment group and the control group randomly，44 cases in each group.The treatment group was given Xiangdan injection combined with low molecular dextran for treatment，while the control group was given magnesium sulfate injection for treatment.Compared the maximal systolic flow velocity of umbilical blood flow/end diastolic blood flow velocity(S/D)， resistance index(RI)，and pulsatility index(PI)，recorded the cases of term delivery，and observed occurrence of adverse reactions before and after treatment in both groups.Results：Before treatment，there were no significant difference between the comparisons of S/D，RI，and PI in both groups(P ＞ 0.05).After treatment，S/D，RI，and PI in both groups were all decreased when comparing with those before treatment，differences being significant(P ＜ 0.05).S/D，RI，and PI in the treatment group were all lower than those in the control group，differences being significant(P＜0.05).The rate of term delivery was 95.45%in the treatment group and 79.55%in the control group，difference being significant(P ＜ 0.05).During the treatment of two groups，there were no obvious abnormalities in four indexes including liver and kidney function， blood routine， urine routine， and coagulation.Conclusion： The therapy of Xiangdan injection combined with low molecular dextran can reduce umbilical artery blood flow resistance of patients with increased umbilical artery blood flow resistance in late pregnancy and increase therate of term delivery.