The present invention relates to a composition for inducing embryonic stem cell differentiation comprising a MEK/ERK (mitogen-activated protein kinase kinase/extracellular regulated kinase) signal transduction inhibitor and BMP (bone morphogenetic protein), and a method for inducing differentiation of embryonic stem cells into mesodermal cells using the same. Further, the mesodermal cells obtained by the above method are able to differentiate into various mesenchymal tissue cells. In particular, the present invention relates to a method for inducing differentiation into hemangioblast by culturing the mesodermal cells obtained by the above method in the presence of VEGF (vascular endothelial cell growth factor) and bFGF (basic fibroblast growth factor). The differentiated hemangioblasts can be further differentiated into vascular endothelial cells, vascular smooth muscle cells, and hematopoietic stem cells under various culture conditions.