Endothelial progenitor cells (EPCs) promote angiogenesis and play a pivotal role in endothelial repair and re-endothelialization after vascular injury. Transient receptor potential-canonical1 (TRPC1) has been recently implied to play important roles on EPC function. Here, we studied the role of TRPC1 in regulating EPC function in vivo and in vitro. EPCs were cultured from TRPC1-knockout mice and their controls. In vitro, TRPC1 knockout reduced EPC functional activities, including migration and tube formation. Additionally, calmodulin (CaM)/endothelial nitric oxide synthase (eNOS) signaling activity were downregulated after TRPC1 knockout. Administration of CaM or eNOS inhibitor ameliorated TRPC1 knockout-reduced EPC migration and tube formation. In vivo Matrigel plug assay confirmed that TRPC1 knockout decreased formation of functional blood vessels of EPCs compared with wild-type EPCs. Taken together, these data suggest that TRPC1 is a critical regulator of angiogenesis.