Co-innovation is a collaborative innovation development model for large，medium and small-sized enterprises to integrate and complement resources，synergistically share knowledge，and create value together through the integration of different entities （industry partners，knowledge partners，government agencies，innovation agencies，etc.）in external innovation networks. This report analyzes the concept of co-innovation，explores the business practice of co-innovation based on case analysis，analyzes how to build a guarantee system for co-innovation，and proposes countermeasures and suggestions to promote the development of co-innovation，such as strengthening platform functions and deepening the construction of an innovation ecosystem and so on.