After the five-stage preheater of our company's 5 000t/d cement clinker production line was upgraded to a six-stage preheater, the SNCR denitration system encountered problems such as low denitration efficiency, increased nitrogen oxide emission concentration, and excessive ammonia water consumption, resulting in a significant increase in operating costs. To meet the emission concentration limit requirements and reduce operating costs, measures such as detection at each node, re-arrangement of spray guns, and trial-and-error elimination were taken. Through debugging and comparison of the SNCR denitration system, the set goals of reducing nitrogen oxide emission concentration, significantly reducing ammonia water consumption, and lowering operating costs were achieved.