The Bologna Process has led to the reform of the higher education diploma system in Germany, which in turn triggered changes in the country's teacher-development system. The two-stage diploma program (bachelor and master programs) has replaced the traditional one-stage structure, where a national qualification test was used as the single criteria for the teacher-development system. The purpose of this research was to explore the introduction process of the two-stage diploma program and explain its system structure and reformative progress. An analysis on the relevant reformative issues was also conducted by studying the official policy documents and relevant research papers. In sum, the two-stage diploma program in Germany is characterized by the extensive adoption of an integrated program model, while in the meantime enforcing a two-fold reform in both the higher education and the teacher-development system. This approach allowed the co-existence of traditional and new systems, leading to increased and diversified course models. According to the above results, the researcher made some suggestions about the reform of the teacher-development system in Taiwan.