Presently,there is a common conclusion on the sexual life model“tying waistband”of Yugu ethnic group:it is the matrilineal relic.

In Yugu's conception,child's boneis from father,blood and flesh are from mother.As the key of individual transmissibility,“father's bone”is the substance which would not reduce during forever generational transmission.People from the same male ancestor share same bone and surname,they call each other“the same family”,which is Yugu's consanguinity.

Basing on cultural and social consanguinity,Yugu people used to practice two sexual life models,one is matched marriage,the other is tying waistband.Matched marriage has different forms.No matter what form,all born child use male's surname.Tying waistband is also the social formal marriage,but female and male in this type of marriage do not have necessary affection and economic connections.A woman chooses tying waistband is in purpose of finding surname for her children to gain social admit.

As basic social logic,the defining system of Yugu's individual identity is clearly male-oriented.Matched marriage and tying waistband have shown the key role of male's surname and full inheritance.As expression of cognition on individual life and surrounding existence,Yugu's conception on space and time specifically emphasizes male's family and social role,and female's attaching role to male.

In the sum,our conclusion is that Yugu society is a patrilineal society.“Tying waistband”is just another variation of sexual life models in the patrilineal system.

Key Words: Yugu Sanguinity Consanguinity Sex taboo Kin-term system Time Space