Monochorionic twin sheep without complications and comorbidities are usually born at 35 to 37 weeks of gestation, but those with comorbidities need to terminate the pregnancy at the appropriate time according to the intrauterine condition of the fetus and in accordance with medical advice. Monochorionic twin sheep refers to monochorionic twin amniotic sac twin fetuses, due to the two fetuses share a placenta, prone to twin transfusion syndrome, selective fetal growth restriction and other serious complications, so need to strengthen the management of pregnancy, regular ultrasound to monitor fetal growth and development, no complications can be terminated at 35~37 weeks of gestation, there is a comorbidities should be according to the intrauterine situation of the timely termination of pregnancy. Twin pregnancies are high-risk pregnancies, especially monochorionic twin pregnancies. During pregnancy, it is necessary to strictly follow the obstetric examination on time, conduct ultrasound examination every 2 weeks to monitor fetal growth and development, and early detection of whether there are special complications of monochorionic twin fetus, etc. When complications are suggested to occur, it is necessary to promptly refer to hospitals with the level of treatment and give intrauterine interventions, in order to reduce the risk of pregnancy.