With the integration and development of digital economy and real economy， building digital platforms has become an important business model choice for the digital transformation of traditional enterprises. It adopted a longitudinal case study method， focused on the construction process of the i5 platform， and analyzed the capability foundation and process mechanism of the digital platform business model innovation based on the dynamic capability theory. It divided the construction of digital platforms into startup， construction and expansion. It finds that traditional enterprises make platform-based adjustments to business model components through the deployment of dynamic capabilities at the enterprise， network and system levels， which promotes the construction of platform value propositions， closed-loop value networks and multilateral digital platforms， and gradually realizes digital platform business model innovation. The research conclusions enrich the exploration of dynamic capabilities at the network and system levels， strengthen the potential of dynamic capabilities to explain business model innovation phenomena， and make up for the lack of attention to the dynamics of digital platform research by describing the evolution of the platform. The difference between digital platform and traditional platform was analyzed. There is great significance to the digital transformation of traditional enterprises and the breakthrough of inherent path dependence to achieve business model innovation.