The linear dynamic rheology of polymer melts filled with nano-sized fillers is investigated in relation to a proposed two phase model. A common principle is disclosed for nanofilled polymers exhibiting either fluid- or solid-like behaviors with increasing filler volume fraction. The bulky polymer phase far away from the filler inclusions in the nanocomposites behaves the same as in the unfilled case while its contribution to the composite modulus is enlarged due to strain amplification effect. The filler forms aggregates together with polymer chains absorbed on the filler surface, which is termed as the "filler phase" in the proposed model. The dynamics of the "filler phase" slow down with increasing filler concentration. The applicability of the proposed two phase model is discussed in relation to the well-known structural inhomogeneity of nanofilled polymers as well as the strain amplification and the filler clustering effects. (C) 2010 Elsevier Ltd. All rights reserved.