Objective To explore the effect of Taishan Panshi powder combined with dydrogesterone on unexplained recurrent abortion(URSA)and its mechanism.Methods A total of 180 URSA patients at early pregnancy who were admitted to Guangdong Maternal and Child Health Hospital from January 2021 to June 2022 were enrolled and randomly assigned(1∶1)to combined group or control group.The control group was treated with dydrogesterone,and the combined group was treated with Taishan Panshi powder on the basis of dydrogesterone.The clinical efficacy,delivery outcome,TCM syndrome score,coagulation function(fibrinogen[FIB],platelet count[PLT],and D-dimer[D-D]),helper T lymphocyte 17(Th17)/regulatory T lymphocyte(Treg)level,the mRNA expression of retinoid-associated orphan nuclear receptor γt(RORγt)and spiral transcription factor(Foxp3),and the incidence of adverse reactions were compared between the 2 groups.Results The total effective rate of the combined group was significantly higher than that of the control group(P<0.05).After treatment,the TCM syndrome score and the levels of FIB,PLT,and D-D of the combined group were significantly lower than those of the control group(P<0.05).The combined group had higher success rate of delivery than the control group(P<0.05).Th17/CD4+ and Th17/Treg in the combined group were lower than those in the control group,while Treg/CD4+ was significantly higher than that in the control group(P<0.05).The combined group had lower RORγt mRNA level and higher Foxp3 mRNA level than the control group after treatment(P<0.05).There was no significant difference in the incidences of adverse reactions between the 2 groups(P>0.05).Conclusion Taishan Panshi powder combined with dydrogesterone has a significant effect in the treatment of URSA.It can improve hypercoagulable state,maintain Th17/Treg immunologic balance by regulating the expression of RORγt and Foxp3,improve symptoms,and increase success rate of delivery with high safety.