Polymers containing ceramics filler are used in various fields that require good thermal conductivity and electric insulation. For material design, prediction of the thermal conductivity is thus critical. There are several prediction methods to determine the thermal conductivity of filler-dispersed composites, such as the Hatta-Taya and Bruggeman models. However, these models do not consider the effect of interaction between fillers; thus, the actual thermal conductivity is larger than the predicted thermal conductivity. In this research, the thermal conductivity of polymers containing ceramic filler was numerically simulated, and the results were compared with the values predicted using the Hatta-Taya model to investigate the effect of filler orientation angle and aspect ratio. The trend of the thermal conductivity change was similar to that observed for the Hatta-Taya model, however, the simulated thermal conductivities were 30% larger than those determined using the Hatta-Taya model for a filler thermal conductivity and volume content of 40 W/(mK) and 25%, respectively. The simulated thermal conductivity results prominently deviated from the Hatta-Taya model values when the filler content ratio was large, the filler aspect ratio was small, or the filler orientation was along the heat-transfer direction.