To investigate the clinical efficacy of Baoyin Decoction combined with dydrogesterone tablets in treatment of early threatened abortion.Methods:A total of 60 patients with early threatened abortion were randomly divided into control group and treatment group，with 30 cases in each group.Control group orally took dydrogesterone tablets，while observation group orally took Baoyin decoction based on control group，with one course of treatment in two groups (3 weeks).The clinical main symptom score and total scores，clinical efficacy，serum β-HCG，P，CA125 levels were compared between the two groups.Results:The clinical effective rate of treatment group and control group were 93.3% and 80%，with statistical difference (P<0.05).The improvement of vaginal haemorrhage，lower abdomen pain or distension，low back pain in treatment group was better than that in control group (P<0.05).After treatment，the levels of P and β-HCG in two groups increased，and treatment group was higher than control group (P<0.05).After treatment，the serum CA125 of two groups decreased，and there was statistical difference between treatment group and control group (P<0.05).Conclusion:Baoyin Decoction combined with dydrogesterone tablets in treatment of early threatened abortion can increase clinical efficacy，enhance the levels of serum P and β-HCG，down-regulate the level of serum CA125，decrease the risks of abortion，achieve hemostasis effects and prevent miscarriage.