The invention discloses a neutral detergent which consists of the following raw materials by weight percent: 30-50% of main detergent, 0.5-2.5% of surfactant, 0.2-2.5% of penetrant, 2-8% of cosolvent, 15-25% of base and the balance of water, wherein the pH value of the detergent is 7-9; and the main detergent is a polycarboxylic acid compound and/or organic carboxylic acid compound. Compared withthe prior art, the neutral detergent has the beneficial effects of thoroughly clearing hard scale, having no corrosion on metal, enamel, glass and the like and having no toxicity on a human body, anda waste liquid can be completely discharged and recycled, thus the detergent disclosed by the invention is an environmentally-friendly neutral detergent which is efficient and safe; and by using the neutral detergent, stubborn scale on the surface of a heat exchange element of GGH of a desulfurization system can be rapidly and effectively cleaned with the cleaning period of 5-7 days, and the cleaning effect can reach an assessment criteria for a power plant performance test, thereby contributing to energy conversation and emission reduction.