A method and apparatus for rationalizing the allocation of the heat energy generated from catalytic combustion process for enameling machines wherein a circulating fan is installed above the oven body in a position close to its middle portion; above the front area of the oven body is an organic waste-gas inlet and above which is a primary catalytic chamber. A hot-air allocation chamber is located on the side of the said primary catalytic chamber. The said circulating fan connects the said primary catalytic chamber and the hot-air allocation chamber, delivering the circulating hot air resulting from catalytic combustion into the hot-air allocation chamber which is further connected to the front area, middle area and back area of the oven body via the front air flue, middle air flue and back air flue. With rationalized distribution of heat energy, this invention accelerates the baking speed, thereby improving productivity by 20%. By ensuring effective collection of the waste gas for secondary catalytic combustion and the repeatedly primary catalytic combustion of the circulating hot air, the emission is lowered to 50 mg/m3. Moreover, this invention utilizes the heat energy produced from catalytic combustion process for baking purpose, which helps save power consumption by 50%.