Given the rapid development of digitization, social media has become a key platform for digital campaigns to promote business and products, with an aim of maximizing profits. Yet, empirical evidence on the performance of a digital campaign for smart tourism and on-line purchasing remains under explored. Using an innovative design of an ecosystem for both smart tourism and on-line purchasing promotion becomes an important tool especially during mobility restriction due to COVID-19. The research was carried out studying the construction and operation of an ecosystem for smart tourism and on-line purchasing of one case of China. Key findings identify components of the ecosystem and its working mechanisms promoting smart tourism and on-line purchasing, and reveal the performance of the digital campaign. Although a larger data amount should be grasped by designing a more comprehensive ecosystem, results of the research show the effectiveness of social media as a marketing platform for smart tourism essence as “products”, and how an ecosystem is constructed and applied at a smart tourism destination, together with its logic combining and promoting smart tourism together with on-line purchasing.