Tibet Autonomous Region plays an important role in the “Belt and Road Initiative”. The BRI’s both internal and external implications determine that Tibet’s involvement in the BRI has two directions：domestic economic integration and opening to the outside world. The development and opening-up of Tibet is a trend that is irreversible. However，Tibet has to face a series of international strategic and security challenges in its external connectivity and opening up，due to its unique role as an important national security barrier，an important ecological security barrier，an important reserve base for strategic resources，an important area for the protection of China’s unique ethnic culture and a popular tourist destination，and a frontline where China encounters western hostile forces and separatist forces. Tibet’s external connectivity and opening up is relatively more difficult. Thus，Tibet’s involvement in the BRI should focus more on domestic economic integration and internal connectivity. At the same time，Chinese government should pay more efforts to shape a suitable international circumstances，and Tibet Autonomous Region should make solid preparation to connect with South Asian countries.