This paper offers a brief description of the Taiwanese elementary school system. It also outlines the current teacher training system, emphasizing the differences between the old "Normal Education Art" and the new "Teacher Education Art". One section describes the three major reforms that Taiwan's mathematics curriculum has undergone in the last three decades. Another section proposes two approaches aimed at assisting teachers in effectively dealing with reforms in mathematics education, and describes the effect of these reforms on teacher development. The paper states that developing cases of teaching was found to be a rich vehicle through which to facilitate teachers' reflective thinking. In addition, cases of teaching can serve as prototypes for developing essential knowledge about teaching events and can be used as precedents to provide occasions to practice analysis. Analyzing children's solution patterns contributes to a better understanding of their thinking. Furthermore, group discussion provides a forum for debate and reflections. Social interactions, cognitive conflicts, and reflections upon research are catalysts for developing teachers' knowledge. The sharing of beliefs and experiences among teachers on a collaborative team serves teaching practice and supports change in teachers' beliefs and conceptualization of mathematics teaching and learning. (Contains 13 references.) (ASK)