ER71 (Etv2, Etsrp) has been identified as a crucial transcription factor for differentiation of hematopoietic and endothelial cells during early embryonic development. However, little is known about the roles of ER71 during angiogenesis in adults. Here, we investigated ER71 expression in vascular development from embryo to adult using Etv2/ER71-venus knock-in mouse. In embryos, ER71 was expressed in Flk-1+ mesodermal cells and endothelial precursor cells, but not in fully differentiated endothelial cells. In adult mice, ER71 was not expressed in physiological condition or during pathological angiogenesis including wound, inflammation, and tumor. We also confirmed that ER71 is indispensable for blood vessel development before E10.5, and that genetic deletion of ER71 does not affect embryo development after E10.5. Our study demonstrated that ER71 is specifically important for embryonic vasculogenesis and is dispensable for angiogenesis in adult.