Microvel double velour graft impregnated with a biodegradable algin was studied as a new vascular graft. It is blood tight but still retains high porosity. Thls graft does not need to be preslotted with blood before implantation and has good tissue ingrowth and biological healing properties. The algin impregnated vascular graft was investigated by "in vitro" tests in this study. It was characterl zed by ESCA analysis, SEM observation, and measurements of water permeability, algin coating weight, mechanical properties and whole blood clotting time. The water permeability of the graft was reduced more than 99% and the whole blood clotting time was fast more than three times by the algin impregnation treatment. "In vivo" performance examinations of the algin impregnated graft are on progress.aft are on progress.