This thesis presents an analysis of the way in which the Chinese research system has evolved from a closed and centrally planned system to a more open one, which shares many of the features of research systems in North America and Western Europe. It argues than in addition to top down reforms of the organisations which populate the different level of the Chinese research system this development was made possible by the return of foreign trained researchers. These returnees introduced not only the latest scientific knowledge and skills, they had also been socialised in a Western research setting. The introduction of these actors helped facilitate the institutional and organisational changes which took place in the last decade. In addition these returnees possessed an international scientific network and by remaining in contact with their foreign peers they helped the Chinese research system to 'open up' to the rest of the world. The main aim of this thesis is to explore how the Chinese research system in general and China’s plant molecular life science research in particular has evolved and internationalised in the past twenty years, and what role scientific mobility has played in this process. Part I presents the theoretical and methodological framework upon which the analyses in the three further parts are based. Collectively, the analyses presented in four chapters of Part II aim to provide an insight into how the Chinese research system has modernized and internationalized in the past two decades. The three chapters of Part III use bibliometric analyses to provide an insight into the changing role of the Chinese research system within the global science system and how this change is related to patterns of scientific mobility. Finally the three chapters of Part IV are built on individual level data and their main aim is to explore the different roles of returned scientists in more depth. The concluding chapter 15 returns to the research questions formulated in chapter four and to how these questions have been answered by the analyses presented in the different chapters. It continues by discussing the potential implications of these answers to the existing literature and policy.