The efficiency of thermal conductive filler can be significantly enhanced by constructing segregated structure, which was confirmed helpful in forming a continuous thermally conductive network to increase the heat dissipation of polymers, however the relatively poor mechanical properties of segregated structure limited its application. In this work, PP fiber was used to reinforce PP/BN composites with segregated structure. The BN contact areas and the network density were also increased, which resulted in better thermal conductivity of the composite. As expected. The resulting thermal conductive composite exhibits impressively enhanced elongations at break and tensile strength: a increased of 57.16 % and 50.84 % were observed for the composite with 6wt % PP fiber compared with the sample without PP fiber. What’s more, the thermal conductivity of the sample with 6 wt% fiber was markedly increased by 81.5 % and 53 % compared with the composites with randomly dispersed hybrid network and the segregated structure without PP fiber. The results offer some insights into the design of segregated network in polymer composites with high thermal conductivity, as well as good mechanical properties. Keywords: thermal conductivity, mechanical properties, segregated structure, fiber reinforced, boron nitride