TiH₂ powder has been used to fabricate aluminum foams as a blowing agent for more than two decades. The aim of this paper is to understand the detailed decomposition behavior of TiH₂ powder and to control the phenomenon by a heat treatment for the fabrication of fine aluminum foams by the melt route. TiH₂ powders whose qualities were different, were characterized using TG-DTA and XRD. As heat treatment factors, temperature and time were applied. We have found differences in the decomposition behavior between the as-received TiH₂ powders. Regardless of quality of TiH₂ powder, increasing temperature and time of the heat treatment in air elevates the decomposition temperature and decreases the amount of released hydrogen during reheating due to the oxide barrier layer formed on the powder surface. The influence of the heat treatment temperature on the decomposition modification is more significant than that of the time. To control the decomposition phenomenon of TiH₂ powder, the heat treatment condition has to be optimized taking into account the quality and the purity of the powder.