With the rapid application of Web2.0 and the rise of social media, social-commerce has become a research hotspot in the field of marketing and information systems. This new business form which is driven by the user's social interaction, is considered as a new paradigm in current e-commerce research field. However, current studies are mainly limited in the field of marketing, the law of s-commerce’s evolution and its impact on the traditional e-commerce is not been fully considered. In recent years, China’s s-commerce has developed rapidly and has not received enough research attention. This study selects Taobao.com and PingDuoDuo as typical cases to analyze the “network stream dilemma” of the traditional e-commerce platform and the solution in the s-commerce context. We conclude that traditional e-commerce platforms are evolving toward s-commerce driven by the change of network stream distribution mechanism.