The American education reform is based on the concept of accountability, which is also the foundation of the No Child Left Behind Act (NCLB) and Elementary and Secondary Education Act (ESEA). It has shifted the traditional approaches to actively pursuing the standards reached (standards-based reform). The traditional accountability system emphasized population data such as student-teacher ratio, enrollment rates, and dropout rates; on the other hand, the new accountability focuses on the student learning outcomes (student performance) as a basis for performance evaluation. Although the government, scholars, and civics hold different views on the aspects of performance, they share similar perspectives on the role of accountability in school education. This review covers the introduction of the NCLB policies and the new accountability theory, then discusses the problems and challenges after a decade of NCLB policies in the United States. Adequate Yearly Progress (AYP), Highly Qualified Teacher (HQT) and NCLB Choice Provision are used as examples to elaborate the further concerns that may be raised by the NCLB policies. This study concludes that while well-meaning, some NCLB policies were not practical. Research suggests that a reviewing and assessing mechanisms should be established for education reforms, utilizing a credible research system and focusing accountability on student growth, in order to provide valuable reference for education reform in Taiwan.