TiB₂ dispersed aluminum alloy was synthesized by the reaction. Starting materials used in this experiment were titanium, AlB₁₂ and AlB₂. The heat of reaction between titanium and AlB₁₂ was too high to maintain the original configuration of the powder compact. Thermodynamical calculation reveales that the adiabatic temperature of the reaction between titanium and AlB₁₂ exceeds the boiling temperature of aluminum. Titanium and aluminum were added in the [Ti, AlB₁₂] powder mixture to control the adiabatic temperature of the reaction. The addition of both titanium and aluminum can successfully control the adiabatic temperature. The average size of the TiB₂ particles was strongly depends on the amount of titanium added as the diluent of the heat of reaction. As the amount of titanium addition in powder phase increases, the average size of TiB₂ particles, synthesized by the reaction, decreases. Differential thermal analysis (DTA) data reveales that the reaction between titanium and AlB₂ initiates at around 1280 K (the decomposing temperature of AlB₂) whereas the reaction between titanium and AlB₁₂ does not occur at temperatures below 1473 K. The addition of aluminum powder in powder mixture of [Ti, AlB₁₂] system, however, contributes to decreasing the initiation temperature of the reaction.