The heat decomposition of TiH2 was researched with a thermogravimetry (TGA) method. TiH2 powder was heated up at different heating rates under the vacuum condition, and then it was decomposed. The initial temperature of decomposition was between 550 and 580 oC, and did not greatly increase with increasing of the heating rate; but the termination temperature was increased. The mass loss of TiH2 decomposition increased with increase of the heating rate, but the time of TiH2 decomposition was reduced