Abstract： Objective： To observe the clinical effect of syndrome differentiation and treatment of threatened abortion based on the KY3H Chinese Medicine Constitution Identification-Assessment-Intervention System in addition to conventional treatment. Methods： A total of 600 cases of patients with threatened abortion treated at Wenzhou Traditional Chinese Medicine Hospital of Zhejiang Chinese Medical University from July 2022 to June 2023 were selected and divided into the control group and the observation group according to the random number table method， with 300 cases in each group. The control group received conventional treatment，and the observation group addition to the conventional treatment received by the control group，used the KY3H Chinese Medicine Constitution Identification- Assessment-Intervention System to determine the Chinese medicine constitution type of each patient and was further treated with targeted Chinese medicine decoction based on their constitutional types. Both groups were treated for two weeks. Clinical effects， sex hormone levels， and success rates of fetal protection were compared between the two groups. Results：After two weeks of treatment，the total effective rate was 93.00%（ 279/300） in the observation group， higher than that of 87.67% （263/300） in the control group， with a significant difference （P＜0.05）. The levels of progesterone （P）， estradiol （E2）， and human chorionic gonadotropin （HCG） in serum in the two groups were increased when compared with those before treatment，and the levels of P，E2 and HCG in the observation group were higher than those in the control group，differences being significant （P＜0.05）. The success rate of fetal protection was 90.67% （272/300） in the observation group， higher than that of 83.67% （251/300） in the control group， with a significant difference （P＜0.05）. Conclusion：The KY3H Chinese Medicine Constitution Identification-Assessment- Intervention System，when used in addition to conventional treatment，can improve the levels of P，E2，and HCG in serum，and enhance pregnancy outcomes in patients with threatened abortion.