The dynamic rheological behavior of high-density polyethylene (HDPE) composites filled with carbon black (CB) was studied by controlling periodic small shear strains at constant temperatures. The results shed light on the relationship between the behavior of dispersed fillers and polymeric matrix systems. At sufficiently high filler concentration a structural skeleton seems to appear, which significantly raises the modulus at the low frequency region. High structure, finer size acetylene black raises the modulus significantly more than dues the low structure and larger size one (e.g., N550). Oxidized CB increases the modulus in the whole frequency region for the enhanced interaction between polymer matrix and CBs.