When the proportional,integral and differential regulation system(named as PID) is used for the heat effect control of industrial furnaces and kilns which burn the fuel oil, there are two forms of control,in general, to meet the need in the different heating stage: First,the oil-air ratio and the feed of burning nozzle are controlled concentratedly and continuously; Second, the numbers of burning nozzels used in the working are controlled dispersedly and discontinuously. The emphatic discussion in this paper is the second regulation form of PID system which can overcome the disadvantages of the fist regulation,has advantages of energy saving,less burning loss and low pollution etc,and provides a good way to the control of optimal heat effect.