The study aims at exploring the inner relationship among the corporate entrepreneurship, upgrading and firm performance. Building on knowledge-based view and capability theory, we put forward several theoretical hypotheses and test them with an extensive survey within four industrial clusters in Zhejiang Province. The findings show that: (1) Corporate entrepreneurship is an important way by firms to create and acquire knowledge, and could improve performance of clustered firms; (2) Capability is built upon knowledge. No matter what kind of upgrading it is, they are manifestation of capability development. Firm upgrading mediates the relations between corporate entrepreneurship and firm performance. Theoretical and practical implications of our findings are discussed.