[[abstract]]This study attempts to expound the basic concepts of U.S. charter schools, the charter schools' development and implementation in U.S., and to explore the impact of charter schools. Based on the research findings, the recommendations are offered as the improvement for education reform in U.S and Taiwan. To achieve the above purposes, the research adopted the methods of literature review and interview. Firstly, through literature review, charter schools' concepts, historical development, future prospects, teaching and learning, governance, accountability, problems, etc. were discussed. Secondly, interviewing three California charter schools' administrators and the executive director of California Network of Educational Charters ...