In the Internet age, the traditional mode of upstream fresh supply chain can no longer meet the diversified demand of the sales end, which restricts the long-term development of fresh retailers. Aim at this problem, we analyze the different advantageous resources and the "Internet +" supply chain upgrade paths of Baiguoyuan and Missfresh. Then, the research finds that fresh retailers with heterogeneous resources will choose different "Internet +" supply chain upgrade paths based on their own advantageous resources, including the co-construction supply chain upgrade path and the leading supply chain upgrade path. The characteristic of co-construction supply chain upgrade path is fresh retailers combining suppliers to acquire new resources and develop core competencies to connect stakeholders in the supply chains. They can access Internet technology resources and upgrade supply chains by constantly exploring the upstream and downstream of the industrial chain. This is built on the strong connection between fresh retailers and upstream suppliers and the logistics advantages of physical stores. The characteristic of leading supply chain upgrade path is fresh retailers using their technical advantages to promote supplier resources upgrading. They attract more and more consumers to form large-scale data through social marketing, membership reforming, and continue to tap consumer demand, increase the influence of fresh retailers on the supply chain. This is built on the fresh retailer’s data resources, technical advantages and online sales platform. Finally, we find that the nature of retailers and suppliers, network relationships and advantage resources are the main factor affecting the upgrade path of the fresh chain.