An application of 2,3-dihydro-3 hydroxymethyl-6-amino-[1,4]-benzoxazine in the preparation of drugs inducing embryonic stem cells to differentiate to vascular endothelial cells, wherein the concentration of the 2,3-dihydro-3 hydroxymethyl-6-amino-[1,4]-benzoxazine in the preparation of drugs effectively inducing mouse embryonic stem cells to differentiate to vascular endothelial cells is 1˜20 μM. The 2,3-dihydro-3 hydroxymethyl-6-amino-[1,4]-benzoxazine provided by the invention lays foundation for preparing and developing drugs inducing embryonic stem cells to differentiate to vascular endothelial cells, can be used as an effective research tool of embryonic stem cells, and can be used for researching on embryonic stem cell differentiation and new molecular mechanisms of blood vessel formation.