Background: To analyze the impact of a multidisciplinary collaborative diagnosis and treatment (MDT) management in obstetric outpatient departments on the outcome of high-risk pregnancies, and to summarize the experience and to improve the diagnosis and treatment ability of for critically ill obstetric patients. Method: Two hundred sixty-six pregnant and lying-in women with multidisciplinary treatment were selected for retrospective analysis. According to the criteria, 176 high-risk pregnant women were included, including 83 cases of outpatient MDT and 93 cases of inpatient MDT. The classification of pregnancy diseases and pregnancy risk was carried out. The source of high-risk pregnant women, the distribution and number of collaborative clinics, the classification of major diseases, the classification of pregnancy risk, the mode of delivery, the condition of labor, and pregnancy outcome were all analyzed to determine the impact of participating in MDT timing on adverse pregnancy outcomes through logistic regression analysis. Result: (1) The top 3 diseases in high risk pregnant women undergoing MDT were pregnancy with cardiac disease 42.6% (75/176), pregnancy with hypertension 14.2% (25/176), and pregnancy with immune system disease 11.9% (21/176). Among pregnant women with cardiac disease, 38 (50.7%) were mainly congenital cardiac disease. (2) The number of high-risk pregnant women with MDT in the hospital was more than that in the outpatient department (p 0.05), and the number of departments involved in MDT in the hospital was more than that in the outpatient department (p 0.05). The proportion of pregnant women with pregnancy risk grade of I–III in outpatient MDT cardiac disease was higher than that in inpatient MDT (p 0.05), while the pregnant women with pregnancy risk grade of IV–V were all inpatient MDT cardiac disease with the majority being in late pregnancy (12/16). (3) The high-risk pregnant women who received MDT in the late pregnancy had a red risk level, which was higher than that then in early and middle pregnancy (p 0.05). There was a higher rate of premature delivery, multiple organ damage, intensive care unit (ICU) monitoring, cesarean section, and neonatal asphyxia in high-risk pregnant women with later MDT gestational age (p 0.05). The late timing of participating in MDT was a risk factor for ultimately developing adverse pregnancy outcomes (p 0.05). Conclusions: Outpatient MDT management can effectively improve the pregnancy outcome of high-risk pregnant women, early outpatient MDT mode management should be actively promoted, and a comprehensive and professional MDT team should be utilized to reduce adverse pregnancy outcomes.