3D network structured TiBw/Ti60 composite has been fabricated by reaction hot pressing. The high temperature mechanical properties of the composite were tested in the temperature range of 600~750 ℃. When compared to the Ti60 alloy, the high temperature strength of the composite can be significantly increased by the formation of in situ TiB whiskers with 3D network structure. The ultimate tensile strength of the 5.1 vol.%TiBw/Ti60 composite is increased by 42.5%, 39.9%, 35% and 13.2% compared with that of the Ti60 alloy at 600 ℃, 650 ℃, 700 ℃ and 750 ℃, respectively. However, the elongations of the composite are all lower than those of the matrix alloy. The main crack propagation of the composite with network structure follows the boundary along the network structure. And the fracture mechanism of the composite changes with increasing the experimental temperatures.