China is experiencing a phenomenal expansion of platform economy fuelled by the advancement of information and communication technologies. It has become a global frontrunner in many sectors, including commerce, finance, and entertainment. A comprehensive law and policy narrative, however, is largely absent from English academic literature. This paper seeks to fill this gap by analysing the dynamic relationship of industrial development, policy engagement and regulation construction in one of the prime sectors of platform economy: Electronic Commerce (E-commerce). China's E-commerce market rose to global dominance shortly after its origination in the mid-1990s. This paper holds that such an expeditious ascendency is nourished by carefully designed public policies. To implement these policies, also to redress information asymmetries and other pertinacious market failures, a tailored regulatory paradigm has been instigated. This regulatory paradigm manifests a new mode of polycentric, participatory, and collaborative governance that strives to balance interest disparities between various stakeholders. The dynamic relationship exemplified in China's E-commerce market would provide a valuable indication for administering other sectors of platform economy not only in China but also across other jurisdictions that openly embrace commercial innovations in the context of information technological transformation.