Affinity clans and luandishi ( or luandi clan ) constituted the backbone of the Xiongnu’s social structure, among which luandishi was in the dominant position while those affinity clans were subordinate. But affinity clans’ status in Xiongnu society started to change since Tuqitang became Chanyu( chief of Xiongnu in ancient China ) in 60 B. C. The reason for affinity clans’ change of their position was not only due to their affinity relations with Chanyu, but also due to the internal contradictions on the succession of Chanyu, and the influence of the Han Dynasty’s polices. The presence of affinity clans and the change of their position had played an important historical role in Xiongnu’s social development, thus it is worth of doing an in-depth academic study in this field.