The invention discloses a production process for treating acid gas of reactive-coke-method coke oven flue gas desulfuration and denitrification by using a complex Claus kiln and a treatment system. Aprocess method for treating the acid gas resulting from reactive-coke-method coke oven flue gas desulfuration and denitrification by using a complex Claus kiln process unit is provided, wherein the Claus kiln is originally used for producing sulfur from coke-oven gas treatment acid ammonia vapor in a coking plant. According to the process, original devices and equipment are sufficiently utilized,only conveyer equipment and dedusting equipment for the acid gas resulting from reactive-coke-method coke oven flue gas desulfuration and denitrification are required to be additionally arranged, other energy sources and equipment are not additionally added, and then, contaminants in the acid ammonia vapor of coke-oven gas and the acid gas resulting from reactive-coke-method coke oven flue gas desulfuration and denitrification can be transformed into a chemical product with high added value, i.e., sulfur; the process is simple and reasonable, is free of discharging of wastes such as wastewaterand waste residues and has an unexpected technical effect, and the investment cost is low.