This paper mainly focuses on the autonomous rights of Hong Kong SAR in handling external affairs with the European Union. With the development of Hong Kong SAR’s autonomy, the SAR is handling their own external affairs with the European Union according to the local interests. Therefore, the paradiplomatic activities among Hong Kong and the European countries are booming. The high degree of autonomy that has been enjoyed by Hong Kong SAR is a solid foundation for Hong Kong SAR to participate in paradiplomacy. The thesis aims to analyze the development of paradiplomacy of Hong Kong SAR in its import and export trade relation with the EU after 17 years of handover. The high degree of autonomy brings Hong Kong SAR a lot of advantages and opportunities and also pitfalls and drawbacks to the society at the same time. The handover of Hong Kong shows the world that China offered a new way of decolonization and development afterwards. The development of paradiplomacy in Hong Kong obviously implies that the autonomy in Hong Kong grants by the central government of China is prosperously booming in the SAR.The way to achieve the gains of the formula of “One country, two systems” is complicated and difficult, but the way is the only one