The formation and expansion of the social networks, is a direct-viewing reflection of the life of the Tibetan-in-Nepal. Taking the Social-network as the keyword, this study with the purpose of providing an ethnological case of the Tibetan in Nepal. Since the middle of the 20th century, the Tibetan who have been living in Nepal for more than six decades have gradually built their new social network. By combining the historical context and ethnographic materials (2018-2020), this article aims to present the formation process of this social network and analyse how the social network formed.

Based on the historical process of the formation of the characteristics of the network, three different but important cultural characteristics are revealed:Diversity, Multiplicity and Mobility. Diversity shows that this Social-network, not only the participants which join in are multiple, but every participant constitutes a diverse culture of religious or ethnic or cultural groups. Multi-level points to the fact that the Tibetan social network are not monolithic and unitary, but present multilayer identity selection because of their different ages and cultural elements and political views. And what is more important，their diverse identity traits. Mobility means that like other international immigrants and even local residents, this social network of Tibetan-in-Nepal shows typical characteristics of mobility in other countries and regions. It should be noted that these three characteristics almost run through the formation process of this social network.

In conclusion, this study explains the connection among the Tibetan in Nepal and Relations with neighbouring countries of the Trans-Himalayan region. AND there are two aspects that must be paid attention to the first one is their society and culture gradually adapted to the local society of Nepal, and the second but important one is they also show their adherence to traditional culture.