Drawing on data from two separate ethnographic works，this paper focuses on the institutionalized selection in hospitals and schools. The preparation of the National College Entrance Examination（NCEE）and the pregnancy and parturition are both crucial periods for individuals. Under the eugenic policy and the education for qualities policy，the usage of quantifying instruments and their way of interpretation of numbers in different institutional settings exert influences on the implementation of policies and the production of institutional cultures. In return，the institutional environments limit the power of quantifying instruments，by shaping contextualized interpretation of numbers and their meanings that influence individuals’ action.