As the high performance electronic devices are required the better heat dissipation in electronic packaging is necessary. In this work the thermal diffusivity of epoxy-based adhesive used as an underfill material in electronic packaging can be improved by adding nano-sized inorganic fillers. These fillers including aluminum oxide (Al2O3) silicon nitride (Si3N4) and silicon carbide (SiC) were used alone for preparing particulate filled-epoxy adhesive. Furthermore In order to achieve good dispersion of filler in matrix the adhesive’s preparation process was adjusted. The maximum loading of fillers in adhesive were determined by the homogeneity of filler and matrix. In addition to avoid the agglomeration of filler silane coupling agent was treated onto surface of aluminum oxide filler to improve interfacial interaction between filler and epoxy resin. The effects of the filler type and filler’s loading on the thermal diffusivity of adhesive were investigated using Laserflash.