The factors affecting storage modulus (Ec') and quantitative characterization of polymer composites filled with inorganic particles were discussed in this paper. On the basis of Eshelby’s method and Mori’s work, an equation describing the relationship between the Ec' and the filler volume fraction, particle geometry as well as interfacial morphology was proposed. The Ec' of the glass bead filled low-density-polyethylene (LDPE/GB) composites was estimated by means of this equation under experimental conditions with temperature range of –150-100?C, frequency of 1 Hz and the amplitude of 0.6 mm, and compared with other equations proposed in literature. The results showed that the predictions for this equation were close to the measured data from the LDPE/GB composites.