High thermal conductivity composite has attracted much attention because recent trends for the electronic devices have been higher integration. To make these composite, people have mixed metal, ceramic powders with polymer for achieving both high thermal conductivity (k) and excellent processibility. However, the resulting k could be relatively low because the polymer located between the powders has low k. Here, we assume that bridging particles with high k are added to the polymer and the bridging particles create a direct heat path between the powders. In this case, k of composite could be largely improved. Because heat can escape from the composite well through the bridging particles even though the polymer is still present between the powders. In this research, we set the model which predicted k of composite as a function of k of bridging particles / the powders. Moreover, we calculate enhanced k of heat path connected system compared to k of powder dispersed system.