The aim of this study was to clarify characteristics and issues of school improvement system in California's educational accountability system by analyzing articles of Public Schools Accountability Act of 1999. Since the 1980's, in the United States, the educational accountability system have been regarded as an effective strategy that resolves decline in academic achievement of students. Similarly, in the state of California, by the enactment of Public Schools Accountability Act, the systematic educational accountability system was structured. This educational accountability system consists of Academic Performance Index (API) as academic standard, award program for high performing schools, Immediate Intervention/Underperforming Schools Program (II/USP) and School Accountability Report Cards. As a result of this study, the main points clarified were as follows: (1) in the structure of this system, this system has two steps that are Local Intervention and State Sanctions. And ultimately, the state takes responsibility for the academic achievement of public schools in the state. (2) This system ensures the involvement of parents and community residents in the activity to improve school. This means an emphasis of external evaluation. (3) This system contributes not only the improvement of students' academic achievement but also the progress of the quality in instructional activity wholly. (4) The lack of clarity of school district's role is one of problems in this system. It is needed to development the unshaken functions of each school districts. (5) Similarly, that the involvement of parents and community residents in the activity to improve school is not workable substantially is pointed out as one of problems in this system, too.