Abstract: Twin-twin transfusion syndrome（TTTS） is a serious complication of a monochoric diamniotic pregnancy that may occur, and it has high fatality. Treatments of TTTS include expectation treatment, reducing amniotic cavity puncture of the amniotic fluid and selective laser coagulation of placental vessels（SLCPV）, the present study showed that SLCPV has obvious advantage in improving the survival rate，reducing the long term complications and thus become the first choice of treatment for TTTS. But due to the risk of fetal abortion，premature delivery and premature rupture of fetal membranes , thus how to make early diagnosis, early treatment so as to improve the survival rate and reduce long-term complications has increasingly cause the attention of experts at home and abroad.

Key words: Fetofetal Transfusion, Fetoscopes, Fetoscopy, Selective laser coagulation of placental vessels