Abstract: For makerspace, building internal and external social relationship networks and cultivating and utilizing social capital are effective ways to operate efficiently and realize goals. In the context of mass entrepreneurship and innovation, this paper studies the formation and influential mechanism of makerspace’s social capital. Study shows that community autonomy and maker network community affect the formation of internal and external social capital of makerspace. Social capital of makerspace can be divided into structural, relational and cognitive dimensions. In the form of strong and weak ties, reciprocity norms and trust, as well as common values and visions, social capital can provide makers with environment of knowledge sharing and resource acquisition to realize technology innovation and social profit. Taking the biggest makerspace in Asia-Beijing Makerspace as an example, this paper analyzes its formation process of social capital and relevant influence on makers’ innovation and entrepreneurship. Aiming at fostering makerspace’s effective operation and maker’s innovation and entrepreneurship, we give suggestions to actors including government, society and makerspaces based on structural, relational and cognitive dimensions of social capital.