A molten salt FLiBe is proposed to be one of candidate materials for coolant and breeder in a fusion blanket. However, it is high Pr-number fluid with large viscosity. Therefore, applying it as the coolant for high surface heat flux conditions, we have to develop a new methods to enhance heat transfer of molten FLiBe flowing in a channel by an adequate active promoters. Through the present study of numerical analysis, it is clarified that an averaged Nusselt number of molten FLiBe laminar flow in a channel filled with the porous medium is higher than that in a normal smooth pipe. The larger enhancemnet can be increased with increasing flow velocity, however, the averaged Nu number shows a maximum value because the heat transfer in the radial direction perpendicular to the flow axis becomes relatively reduced with the increase of the flow velocity.