Tissue engineering of composite bone marrow MSCs offers promising prospects for the treatment of chronic ulcers of the lower extremities. The method was to construct tissue-engineered skin using a tissue engineering approach with bovine collagen as a scaffold and autologous MSCs (composite bone marrow MSCs) as seed cells. The results were: the constructed tissue-engineered dermis with composite bone marrow MSCs was transplanted, which improved the healing speed and obtained a more desirable wound healing effect, providing a new therapeutic idea for the clinical treatment of chronic ulcers of lower extremities. Zhao Donghong, Department of Plastic and Reconstructive Surgery, General Hospital of Jinan Military Region