Abstract:     Innovation platform becomes the mainstream paradigm of commercial economy. Open service innovation platform is an important system for enterprises to obtain the necessary resources and improve the success rate of innovation. The construction of open innovation platform by core enterprises not only promotes innovation paradigm change, internal and external integration and rational allocation of innovation resources, but also becomes an important driving force for enterprise development and economic growth. Acquisition and utilization of innovative resources is a key motivation for enterprises to participate in the construction of innovation platform. At present, a large number of innovation failure cases of incumbent enterprises have aroused widespread concern in the academic community. How to overcome the bottleneck and obstacle of innovation and regain the leading position is worth further study. 
    Resource integration includes not only the acquisition of external resources, but also the process of exporting the enterprise′s own resources. Because multi stakeholders participate in the open service innovation platform, the situation of resource integration is more complicated and dynamic. Thus, how to build innovation platform and obtain innovation resources has become an important issue for enterprises to realize open service innovation. What are the key elements of building a service innovation platform and how they affect innovation performance? These problems have not been clearly explained and effectively revealed. Accordingly, the aim of this work is to provide a better understanding of how to form service innovation platform, what are the key elements and how to impacts relationships into service innovation platform. We conduct qualitative research on four groups of cases by grounded theory, as outlined below. 
   In a research methodology section, we show how to selection case, and present case data collection process and encoding analysis, then report code analysis. The research problem of this paper comes from the analysis of the construction process of CE group′s open service innovation platform. CE group is building an open service innovation platform and has attracted many subjects to participate in this process, and has achieved some innovative results. The resource integration attribute is obvious, which is suitable for exploratory case study. The research team has conducted many in-depth communication and exchanges with the founders and senior managers of the case company to have a clear understanding of the process of building an open service innovation platform for the case company, and can obtain more first-hand and second-hand information.
    The case samples are core enterprises CE, connected enterprises E1, E2, E3, E4, and government G., the core enterprises connected enterprises matching method is divided into four groups of cases. The first-hand data were collected by semi-structured interview. The interviewees included case company founder, sales director, sales manager, technical director, etc. the interview time was about 2 hours. The second-hand data collection and sorting include the relevant reports on the official website, literature, newspapers, interview quotations of managers, industry information, etc. NVivo 11 qualitative analysis software was used to code and analyze the interview data. The coding procedure was based on technology, including open coding, spindle coding and selective coding. 
    This paper makes two aspects of analysis through coding based on grounded theory. We analysis on key elements of open service innovation platform, on the other hand, build a theoretical model of core enterprises′ open service innovation platform. This paper divides the key elements of open service innovation platform into basic elements and operation rule elements. The basic elements include action subject, action subject value proposition fit and innovation resource. The operation rule elements include innovation environment and platform governance rules.
    The research follows the internal logic of "connection-interaction-co-creation" to build a theoretical model of core enterprises′ open service innovation platform. We propose the formation of open service innovation platform starts from the conformity of the value proposition of the innovation subject. The core enterprises evaluate the resource attribute of the connected enterprises, and improve the performance of open service innovation through a series of behaviors such as resource connection, resource dissolution and resource flow. The combination of value proposition and subject resource attribute is the precondition of resource integration. It reveals the subdivision dimension of subject resource attribute: resource diversity and asset specificity. 
    In addition, three research propositions are put forward in this case study. Firstly, there are two types of resource integration for core enterprises to build an open service innovation platform: inward oriented and outward oriented, and different resource integration situations have different effects. In the context of inward oriented, more attention should be paid to functional fit when integrating superior resources, while in the integration of general resources focus on perceptual fit in the context of outward oriented. Secondly, in different situations of resource integration, core enterprises have different preferences for resource attribute evaluation of connecting actors. There are more attentions on the evaluation of the diversity of superior resources in the context of inward oriented, and in the outward oriented situation, it is more emphasis evaluate the asset specificity of general resources. Thirdly, the situation of resource integration has a different impact on the service innovation performance of core enterprises. Inward resource integration is easier to promote the gradual-element innovation performance, while outward resource integration is easier to promote the breakthrough innovation performance. This is an important theoretical aspect of our work that is a beneficial exploration and combination for the research of innovation platform and resource integration.

Key words: open service innovation, innovation platform, resource integration, core enterprise, grounded theory