The temperature uniformity of thin film process is an important issue for susceptor in high temperature vacuum system. When the temperature of process is extremely high the uniformity is not only difficult to control, but also hard to maintain. In order to raise the temperature utilization at high temperature which is higher than 1300°C, the heating baffle is introduced for this purpose. As the result, the thermal radiation is economized about 1% in the chamber which contains six pieces of two-inch wafers. On the other hand, the heating baffle also improves the temperature uniformity of the wafer area on susceptor. The results show the temperature difference decreases to 6°C after using the heating baffle, and it shows that an optimum temperature uniformity can be achieved in a self-assembly reactor.