Abstract: Based on the general situation of birth sex ratio in Ankang city from 1982 to 2010, the general situation and characteristics of its evolution were combed, and the gender ratio of the birth population in Ankang city was shown to be higher and persistently higher. The causes for the imbalance of birth sex ratio in Ankang city were analyzed, which mainly included the influence of "boy preference" bearing concept in traditional society, the backward productivity development level, the state policy promotion of family planning and the abuse of modern medical technology, to provide a reference for solving the current population structural defect in Ankang city.

Key words: birth sex ratio, imbalance, fertility preferences, Ankang city