Abstract: OBJECTIVE To observe the clinical efficacy of treating unexplained recurrent spontaneous abortion with Yishen Huayu formular and its influence on serum D-dimer level， platelet aggregation rate (PAR)， resistant index of uterus artery (RI) and pregnancy outcome. METHODS 82 patients with unexplained recurrent spontaneous abortion were randomly divided into two groups: the control group (41 patients) and the treatment group (41 patients). The control group was given subcutaneous injection of low molecular weight heparin sodium combined with aspirin taken orally. The treatment group was given Yishen Huayu formular based on medications given to the control group. Changes of TCM symptom scores， serum D-dimer level， platelet aggregation rate (PAR)， resistant index of uterus artery (RI)， serum β-HCG level at four and eight gestational weeks and pregnancy outcome in two groups before and after treatment were observed. RESULTS After treatment， clinical effective rate of the treatment group was higher than that of the control group and the differences were statistically significant (P<0.05). TCM syndrome score decreased after treatment in two groups (P<0.01)， and the treatment group was better (P<0.05). The differences of PAR， RI， serum β-HCG level at eight gestational weeks in two groups were statistically significant (P<0.05) while there was no statistical significance between two groups in terms of D-dimer level and serum β-HCG level at four gestational weeks (P>0.05). Pregnancy rate of the treatment group were higher than that of the control group (P<0.05). CONCLUSION Yishen Huayu formular combined with western medicine can decrease unexplained recurrent spontaneous abortion patients' D-dimer level， PAR， and RI， and improve uteroplacental blood perfusion， leading to increasing the repregnant rate.