Abstract: This paper investigates innovation activities of firms in national high-tech industry zones from neo-institutionalism perspective. We examine the importance role of institutions both internal and external the firms, as well as their coupling mechanism on firms’ innovation performance. Taking the Nanning national high-tech industry zone as our research example, we find that under the circumstance of both internal and external institutions the activities of pursuing ‘legitimacy’ have positive impact on innovation performance. However, the coupling mechanism of internal and external institutions does not influence innovation performance significantly. Furthermore, we provide suggestions about how to improve the coupling mechanism in order to better the innovation performance of firms.