OBJECTIVE： To investigate the efficacy and safety of methotrexate （MTX），Mifepristone combined with Huayu xiaozheng decoction in the treatment of uterine scar pregnancy. METHODS： 86 patients with uterine scar pregnancy were randomly divided into control group （43 cases） and observation group （43 cases）. Control group orally received 50 mg ultrasound-guided local injections of MTX，once a day+50 mg Mifepristone tablet， twice a day； observation group additionally received 100 ml Huayu xiaozheng decoction， twice a day with warm temperature. The treatment course for both groups was 15 d. Clinical efficacy， HCG levels， mass diameter before and after 7， 14 and 28 d of treatment， and the incidence of adverse reactions in 2 groups were observed. RESULTS： The total effective rate in observation group was significantly higher than control group， the difference was statistically significant （P＜0.05）. HCG levels and mass diameter after 7， 14 and 28 d were significantly lower than before， it gradually reduced by time prolonged， and research group was lower than control group， the differences were statistically significant （P＜0.05 or P＜0.01）. And there was no significant difference in the incidence of adverse reactions （P＞0.05）. CONCLUSIONS： Ultrasound-guided local injections of MTX combined with Huayu xiaozheng decoction shows good efficacy and safety in the treatment of uterine scar pregnancy