The blast colony-forming cells (BL-CFC), which are detected within embryoid bodies derived from embryonic stem cells (ES cells) differentiated for 2.5-3.5 days, have dual-potential of differentiation to hematopoietic and endothelial cells. In this investigation the culture method of BL-CFC was established and colony forming assay, immunofluorescent technique as well as nested RT-PCR was employed to identify the differentiation capacity of adherent and nonadherent cells derived from individual blast colony. The results showed that the adherent cells could intake DiI-Ac-LDL and expressed the endothelium-specific surface markers including CD31, UEA-I and VE-cadherin. In addition, nonadherent cells were capable of developing primitive or/and definitive hematopoiesis potential. High proliferative potential colony-forming cells (HPP-CFC) bearing self-renewal capacity was found in 20% of BL-CFC. It is concluded that BL-CFC derived from embryonic stem cells can generate high proliferative potential hematopoietic progenitor cells. However, the whether BL-CFC can reconstitute the adult bone marrow hematopoiesis in long-term remains to be further determined.