Commercial competition paradigm is changing from competitive advantage which based internal resources to the eco-advantage which from ecosystem consisted of internal and external value network under the background of the Internet economy. Enterprises can’t effectively face the complex and fierce market competition environment which relied solely on internal heterogeneous resources or core competencies, so many firms adopt platform strategy and build a business ecosystem to be out of this dilemma. It could get eco-advantage for platform leaders to leverage the external resources and ability from the business ecosystem. How can platform leaders gain sustainable development depending on the superiority niche in the platform ecosystem? This paper will answer this question by taking JD as an example which is a typical B2C Internet platform. The results of the study are as follows: First, the platform firm is the leader and creator in the early establishment of the platform-based ecosystem, it’s the formational basis of eco-advantages comes from enough quantity and high quality of platform user. User install and demand are not only the important orientations for platform enterprises producing and managing but also the power source for forming eco-advantages and sustainable development. Second, the sustainable development of the platform leader is related to the size and strength of the network effect. The more network effects, the more conducive to get eco-advantages and sustainable development for platform leaders. Third, the platform-based ecosystem is a value network consisted of a large number of network nodes which is a symbiosis relationship by competing and cooperating. The cross-border integration and collaborative development of multi-agent in the ecosystem are beneficial to promoting platform leaders to form ecological advantages and achieve sustainable development. Forth, platform leader, which is the leading species and key species determined the fate of species in the ecosystem, provides a place for value co-creation of multi-species. It is the process of multi-agent value co-creation based on the platform for platform leaders to obtain sustainable development, which is also the result of internal innovation and external open innovation. This study is of great significance to enrich the research of platform enterprise theory and guide the sustainable development of platform enterprise.