This paper examines how entrepreneurs' social capital facilitates venture capital financing for their start-ups. We consider three dimensions of social capital - i.e., the structural, cognitive and relational dimensions - and three stages of the financing decision - i.e., the access, negotiation and action stages. We develop a conceptual model to disentangle the impact mechanisms, namely, the information mechanism of the structural dimension in the access stage, the knowledge mechanism of the cognitive dimension and the trust mechanism of the relational dimension in the negotiation stage. Using China as our experimental setting, we find that the structural and cognitive dimensions facilitate venture capital financing, whereas the relational dimension does not. The results advance our understanding of the interrelationship among the three dimensions of social capital and their impact mechanisms on entrepreneurial financing.