In this article, we discuss several aspects of the national project, the National Science Concept Learning Study, designed to assess elementary, middle, and secondary students' conceptual understanding in science. After a short introduction to provide some history of the project, we describe the processes used in the integrative study, the participants in the research, the involvement of about 30 senior researchers and 80 research assistants, and the findings from the national data. Although the results of Taiwanese students' conceptions in science are similar to those of western countries, some aspects of our students' performance are unique to Taiwanese culture and language. This article concludes with some educational implications from the research findings.