Abstract: The technique of measurement really simulates of coal spontaneous combustion by the No. XK experimental unit loading coal 850 kg. According to the change of gas concentration and coal temperature determined through experiment of coal self-ignite at low temperature stage, and on the basis of hydromechanics and heat-transfer theory, such as, oxygen consumption rate, heat liberation intensity etc. can be calculated at different low temperature stage. lt offers a theoretic criterion for quantitatively analyzing characteristic of coal self-ignite and forecasting coal spontaneous combustion. According to coal exothermic capability and its thermal storage surroundings, thermal equilibrium is applied to deduce the computational method of limit parameter of coal self-ignite.