Self-propagation high-temperature synthesis due to good properties such as low equipment and the economy is a suitable route for the synthesis of engineering materials. In this study effect of activation on SHS synthesis of TiB2-TiC-Ni cermet with 15 wt% Ni content was investigated. Starting materials were activated 3h and under Ar atmosphere. After activation, green powders pressed to cylindrical shape. Synthesis process was done in the tube furnace at the temperature of 1000°C under Ar flow. XRD pattern shows that nanocrystalline TiB2 and TiC were synthesized. The crystallite size of synthesized samples has been calculated by Rietveld method. The average crystallite size of TiB2 and TiC phase in the sample with 15 wt % Nickel was 68 nm and 30 nm, respectively. Also, SEM images show that activated sample have finer and more uniform microstructure.