New water soluble multiwall carbon nanotubes (MWCNTs) containing silver nanoparticles-grafted-hyperbranched polyglycerols (HPG) nanocomposites were synthesized and characterized successfully. In this work, MWCNTs were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet chemcial method. Then MWCNTs containing silver nanoparticles (MWCNTs(Ag)) were used as macroinitiator for ring opening polymerization of glycidol and MWCNTs(Ag)-g-HPG nanocomposites were obtained. Structure of nanocomposites was evaluated by TEM, TGA and spectroscopy methods. With the solubility of MWCNTs(Ag)-g-HPG greatly improved, the new nanocomposites exhibit potential application in biomedicine and nanomedicine.