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Nanodiamonds (NDs) reinforced titanium (Ti) matrix composites with network microstructures were prepared by using spark plasma sintering technique. Spherical Ti particles were modified with polyvinyl alcohol and then crosslinked with the NDs. Finally, the NDs were distributed uniformly on the surface of the spherical Ti particles. The effects of ND contents on the microstructures，thermal conductivity and compression performance of the Ti nanocomposites were studied. The results show that TiC particles are in-situ formed due to the reaction between the Ti and NDs but some NDs are still preserved in the nanocompoties, the NDs/TiC hybrid reinforcements have a three-dimensional network distribution in the Ti matrix and the size of network is 100-200 μm. The results of thermal conductivity test show that the thermal conductivity of the nanocomposites decreases with the increase of the content of the reinforcing phases. The compressive tests show that the Ti-1.0wt% NDs composites have excellent mechanical properties where the ductility of the composites remains high enough while the hardness and strength are greatly improved. The fracture surfaces of the composites show that the cracks propagate along the network-structured boundary. The network microstructures with hundreds of microns play the role of reinforcing beams, while the internal matrix of the network still maintains low hardness and high ductility of the pure Ti. Eventually, the contradiction between strength and ductility of the Ti matrix composites is reconciled effectively.