Silk fibroin/cellulose acetate blend Nanofibrous membranes were prepared by electro- spinning and their performances were evaluated as a heavy metal ion adsorbent. The electrospun nanofibrous membranes were comprised of randomly oriented ultra-fine fibers of 100-600nm diameters. As a result of field emission electron microscope (FEEM), compared with pure nanofibrous membranes, the anti-felting shrinkage of SF/CA blend nanofibrous membranes with 20% CA content was markedly improved after treatment with 100% ethanol. Metal ion adsorption test was performed with Cu2+ as a model heavy metal ion in a stock solution. The pure SF nanofibrous membranes exhibited high metal ion capacities compared with that pure CA nanofibrous membrane. Especially, the SF/CA blend nanofibrous membranes had an exceptional performance for the adsorption of metal ions, and the maximum milligrams per gram of metal ions adsorbed reached 22.8mg/g for Cu2+. This indicated that SF and CA had synergetic effect.