Abstract: Union cataloging under central-branch library system is the main mode of achieving the co-construction and sharing of bibliographic data in contemporary urban public libraries. At present, there are some problems in union cataloging, such as the lack of Unified standard in bibliographic quality control, uneven professional level of catalogers, a large number of duplicated data, the functions of cataloging system software need upgraded, and pay little attention to the construction and use of standardized Library. The suggestion of strategies of bibliographic quality control as follow: libraries consciously fulfilling their responsibilities of data construction and maintenance, establishing unified bibliographic data quality standards, strengthening cataloging training, dynamically examing the performance of cataloging work, and paying attention to the construction and use of standardized databases.

Key words: public library ;union cataloging; bibliography quality control