The thermal conductivity of Mo fiber-reinforced Al 2 O 3 composite was calculated using analytical solutions for effective thermal conductivity. The deviation between calculated and literature data was less than 10%. The influence of constitution on thermal conductivity of dispersion composites was investigated by simulation based on analytical solutions. When the reinforcements are unidirectionally arrayed, their volume, shape and thermal conductivity greatly affects the thermal conductivity of the composite, and the effects on the thermal conductivity parallel to the reinforcement orientation are bigger than those on the thermal conductivity along the perpendicular direction. As the orientation of reinforcements becomes increasingly random, the anisotropy of thermal conductivity becomes smaller and smaller.