Abstract:     Promoting the transformation and upgrading of industrial alliance is the strategic key of innovation to drive high-quality development in China′s new national system. However, the upgrading of industrial alliance is confronting with lots of dilemmas, such as the extremely difficult key technology breakthrough, loose co-innovation, high homogeneity of alliance resources and so on. Most of current studies are related to the evolution mechanism of industrial alliance from perspectives of social network, ecology, self-organization, and focus on co-innovation among actors and evolutionary stability of industrial alliance. But the translation and upgrading of industrial alliance in dynamic innovation environment have been ignored. Fortunately, innovation ecosystem, as a new innovation paradigm in the future, provides new concepts and directions for the continuous upgrading of industrial alliances--developing industrial alliance innovation ecosystem (IAIE). Meanwhile, the existing research concerning the structure and evolution of innovation ecosystem provides theoretical support for the exploration of the upgrading law of IAIE, and the successful upgrading of some excellent industrial alliances in China also provides mounting practical evidence.
   Therefore, integrating the relevant theories of industrial alliance innovation evolution and innovation ecosystem structure, this paper puts forward structural upgrading essence and the upgrading path conceptual model of IAIE. It focuses on the research logic of ‘upgrading pressure--upgrading starting point--upgrading main control point--upgrading result’ to reveal the upgrading law of IAIE, and technology Innovation Strategic Alliance of Agricultural Equipment, IGRS Alliance and TD Industry Alliance are selected for the multi-case study. 
    The research findings are as follows: Firstly, IAIE could be described as a horizontal and vertical network composed of the horizontal subsystems of technology research, product development, market application, vertical network of co-innovation and value adoption. The upgrading essence is the coordinating upgrading between co-innovation network and value adoption network. Secondly, three upgrading paths of IAIE have been refined as: the new value adoption leading upgrading, the radiation upgrading based on core innovation platform and the embedded upgrading of diversity relationship. The starting points of the upgrading path are to identify potential market demand, build a core innovation platform and absorb heterogeneous actors. Based on the differences of upgrading rhythm between co-innovation network and value adoption network, the main control points of the three paths are dominated by value adoption network, co-innovation network and the coordination relationship between co-innovation network and value adoption network respectively. Thirdly, facing the combination of different upgrading pressures, the upgrading starting point of IAIE determines the difference in the upgrading rhythm between co-innovation network and value adoption network, and then forms the differentiated characteristics of the upgrading paths. The matching relationship between the upgrading pressure, existing conditions and the characteristics of the upgrading path of IAIE determines the scientific optimal selection.
     This study is of great significance both in theory and practice. For one thing, it effectively combines and expands the theories of innovation ecosystem structuration and industrial alliance evolution, and fills the research gap of the upgrading paths of IAIE. It focuses on revealing the essence and basic paths of the structural upgrading of IAIE, and deepening the theoretical connotation of the upgrading of IAIE and the understanding of the internal logic in the upgrading process of industrial alliance. For another thing, this paper provides decision reference for promoting the sustainable upgrading of industrial alliance, and helps to guide the industrial alliance to overcome the practical upgrade difficulties such as key technology breakthrough difficulties, loose technological innovation cooperation and high resources homogeneity. 

Key words:  industry alliance, innovation ecosystem, co-innovation, value adoption, multi-case study