According to the basic mechanism of thermal batteries,the heat producing,transfering and releasing during battery discharging were studied.The discipline of temperature variety in the battery could be annalyzed by computer software.Firstly,the battery was divided into reseaus.As the principium of energy balance,the equation of heat transfering during battery discharging was founded;Secondly,the process of heat transfer during the battery discharge was simulated dynamically by the Finite Element Method;At last,the surface and inner temperature of the thermal battery were measured and analyzed during battery discharging.The results show that temperature variety in the battery can be responded correctly during battery discharging.