The formation of high temperature composites in W-C-B system from fine-grained powders in dependence on the ratio of components by using reactive spark plasma sintering was studied. The mixture of W2C and C nanoparticles was used as tungsten and carbon precursors. The W2C and carbon mixture with different ratio of components was prepared by reduction of WO<inf>3</inf> in presence of CH4 in nitrogen inductively coupled plasma. The specific surface area of the mixture was in the range of 36 – 42 m<sup>2</sup>/g in dependence on the content of carbon. The W2C and carbon particles were mixed mechanically with amorphous boron and densified using the spark plasma sintering technique at 1500 – 1700 °C and pressure of 30MPa for 4 minutes. The sintered bodies contained WB2 and B4C phases. The ratio of phase depends on the content of the components in the raw mixture.