A heating system of a batch type reaction chamber for semiconductor device and a method thereof are disclosed. Each heat unit of heating groups has different height and caloric value at right angles according to the divided areas, thereby it can control an uniform temperature incline of the entire process space of the reaction chamber. Also, the reflecting plates are formed by each heating unit, so that the change of the heating unit can be simple. Furthermore, the divided reflecting blocks are adjacently connected to another reflecting block through the radiant wave shielding slit between them, so that the leakage of the radiant wave can be prevented and the reflecting blocks can be separately attached and deattached to each other. Also, the turning member is formed at the lower portion of the reflecting blocks, so that it can be easily attached and deattached.