Abstract: In recent years,a hot topic on how to solve social problems through commercial path has drawn attention from both academic and business communities.From the perspectives of social entrepreneurship,effectuation,and institutional logic,this paper conducts a double case study on how user social entrepreneurship promotes the formation of business ecosystem.Taking two benefit corporations,Smart Air and How Bottle,as the research objects,this study refines six dimensions,including relating users' experience,grafting existing products and technologies in the market,applying business model,creating social value,partnering with companies that share the same value proposition,and joining professional organizations,and then constructs a process model from user social entrepreneurship to the business ecosystem formation.The paper explains the internal logics of how the social entrepreneurship of the core enterprises forms their business ecosystems from three stages:the integration of user social entrepreneurship resources,the balance of commercial and social attributes,and the construction of business ecosystem.This study provides an insight deep into the mechanism of business ecosystem formation and a guidance for social enterprises,commercial enterprises and other participants of business ecosystem.

Key words: social entrepreneurship, business ecosystem, benefit corporation