The effects of W content, Ti powder size and preheating temperature on combustion temperature and combustion velocity in self-propagating high-temperature synthesis (SHS) of Ti-W-C system were investigated. The phase components of SHS were examined. The reaction mechanism was studied. Uniphase (W, Ti)C can be synthesized without being preheated in the condition of W/(Ti+W)&le0.3. Preheating mixtures can accelerate the formation of (W, Ti)C. There are two reaction mechanisms in SHS reaction process, including solution-precipitation and diffusion-solution in solid state.