Based on website visits of 127 urban libraries in the United States, and national reading promotion activities such as "One Book One City", data collected were processed through classified statistics and comparative analysis. The results showed that 78% of "One Book One City" activities were assisted or directly held by the public libraries; public libraries were the most important institutions applying and holding "Big Read" activities; 60% of the surveyed libraries held "Read across America" related activities; every surveyed library had reading programs, extension activities of reading, audio-visual education, library-community interaction and librarian-reader interaction. At the end, the characteristics of American public libraries were summarized, including government support and abundant fund; activities in various forms with rich content, attention were paid to the cultivation of teenagers' reading interest and community reading promotion.