The invention relates to a down-regulated vertical flue combustion regulating method and a heating system thereof for a coke oven combustor. Combustion air in paired regenerative chambers enters a vertical flue through respective independent channels, wherein the combustion air in one of the regenerative chambers enters the bottom of the vertical flue, the combustion air in the other regenerative chamber enters the vertical flue along positions at different heights, and the flow amount of the combustion air in the two channels can be respectively regulated. Compared with the prior art, the method and the heating system disclosed by the invention have the benefits that 1) the sectionalized combustion of the bottom and the upper part of the vertical flue can be independently regulated and controlled, so that the high-heating uniformity of the vertical flue is improved; 2) the highly directional temperature of the vertical flue is controllable and convenient to regulate, so that workers are protected from operating the system under poor environment, manpower is saved, and labor intensity is reduced; 3) the reduction of the amount of nitrogen oxides generated in the process of coke oven combustion is beneficial to environmental protection; 4) a vertical straight-through type structure adopted by an outlet section channel of the combustion air of the combustor is easy to build and is beneficial to the flow of the combustion air.