In recent years, with the increasingly further studies on embryonic stem cells and the recognition of the biologic characteristics of adult stem cells, it has been discovered that adult stem cells have another phenomenon of "plasticity" in addition to the characteristics of strong poten-tial for self-renewal, proliferation and multi-differentiation, which brings us the hope for regenerative medicine --renewing new organ or tissue cells to replace those damagedby injury or diseases. Although the mechanism of "plastic-ity" and its application in the regenerative medicine are still in doubt, thorough exploration in these subjects would open up broad prospects for the use in cell and tissue engineering in the near future.