Abstract:    The rapid development of digital technology has changed the relationship of cooperation and competition among organizations, and the organizational boundary and value creation mode has changed accordingly. Enterprises can use the digital platform to coordinate the innovation activities of different participants, so as to expand and extend the value. Cross-border innovation takes the ecosystem as the carrier, and the product or service innovation carried out by hub firms and different participants around the digital platform is a complex value co-creation process with dynamic characteristics. In this ecosystem structure, hub firms actively cooperate with different participants, engage with shaping a new innovation environment and create and capture of cross-border value through governance to internal and external participants of the organization.By reviewing the existing literature, the innovation ecosystem is an important context for firms to break boundaries and create value with multiple participants. It can be regarded as a coordination structure formed by different participants around a complex value proposition, including suppliers, complementors and users. With the entry of participants in different industries, the innovation ecosystem has expanded into a cross-border ecosystem on the interaction between participants and users. This paper describes different types of cross-border innovation models from the two dimensions of activity focus and control focus and summarizes them into four types: hub firm leading, user demand leading, open innovation leading and ecosystem leading. On this basis, assisted by case analysis, this paper summarizes the micro mechanism and process mechanism of cross-border value co-creation driven by resource heterogeneity effect, knowledge spillover effect, direct network effect, indirect network effect and digital isomorphism effect.The paper points out that: (1) It is emphasized that cross-border innovation is a dynamic process rather than a static one, and enterprises need to control and govern different types of cross-border models; (2) The logic of cross-border innovation is the transition process from single innovation activity to multiple innovation activities, and the interdependence between innovation participants is the key source of building a cross-border ecosystem; (3) This paper puts forward the theoretical framework and future research direction of value co-creation process mechanism in cross-border innovation, which has strong theoretical value. In addition, in the context of the digital economy, a large number of participants such as suppliers, complementors, users and even competitors have joined the innovation activities of enterprises, resulting in the cross-border activities of enterprises breaking through a single ecosystem category and emerging a more complex and dynamic ecosystem.Therefore, the mechanism of the formation of value co-creation reveals the new relationship between resource integration in cross-border innovation and provides useful inspiration for firm innovation development and digital transformation.

Key words: digital economy, cross-border innovation, innovation ecosystem, value co-creation