Abstract: The SHS reaction of Ni-Al powder compact was analyzed by DTA test. The combustion state was observed while heating Ni-Al powder compact in a vacuum furnace. XRD analysis was conducted to determine the combustion products. Heat transfer theory was used to analyze the effect of specific surface area on the actual combustion temperature of powder compact.Theoretical formula was obtained by related derivation, and the effect of different heat transfer modes was compared. The results indicate that the SHS reaction of Ni-Al powder compact consisted of three stages: solid-phase reaction, emergence of eutectic liquid and the sharp reaction. Increasing the specific surface area of Ni-Al powder compact caused higher actual combustion temperature. The quantity of lost heat from Ni-Al powder compact to surrounding environment was larger by conduction than by radiation.