Following three aspects will help understand the power and the truth of how Tibetan society maintains its unity of religion and politics until modern times. First, it is Dalai Lama, the head of the unity of religion and politics, and high-ranking monks who are close to Dalai Lama. Second, it is Buddhist temples that hold strong influence to design and construct Tibetan politics and religious culture. Third, it is a power block of Tibetan noble families. However, the previous Tibetan society before 1951 formed the ruling class comprised of three types of lords, including government officials of a feudal local government, the nobles, and the high-ranking lamas of Buddhist temples, and their population only accounted for 5% of the total population. Among them, the aristocracy was the actual power group that created Tibetan culture and politics and took the lead in economy. Historically, the Tibetan aristocracy formed four types of classes as follows. The first class is Yabshi family. They are called "Golden aristocrats"consisted of parents of Dalai Lama and a family of Panchen Lama. The second class is Depon family. This family, the most influential group in Tibetan noble society, is traditional and authoritative and passes one power to blood-related descendants. The third class is midak family. This family used to dominate ministers of then Tibetan local government and actively pushed forward marriage among similar families to maintain families’ stability and status. At the time, this marriage culture affected other noble classes except for Yabshi family and led up to the universal sentiment that recognizes politicization of marriage. Lastly, although they are ordinary nobles, they are small self-made families that accumulated economic wealth by their own efforts and entered into the world of nobles. This article will analyze the noble families’ marriage forms, values, and marriage purposes. The analysis intends to reveal that the marriage of then noble families was extremely political by highlighting the difference from the marriage culture of common peasants and serfs in Tibet and additionally estimate the social background at the time to see reasons of the politicization of the marriage.