The invention discloses a method for producing industrial grade diammonium phosphate from wet-process phosphoric acid. The low-cost wet-process phosphoric acid is adopted as a raw material, and undergoes neutralization reaction with ammonia twice to prepare the industrial grade diammonium phosphate; a pickling procedure is adopted, so that volatile gas materials are recycled, crystallization mother liquor is recycled or concentrated for recycling, the industrial grade diammonium phosphate product is obtained, and the product yield is improved; meanwhile, byproducts in the production process are used as compound fertilizer materials. The method greatly reduces the production cost of the industrial grade diammonium phosphate, ensures the stability of product quality, avoids secondary pollution, and has low energy consumption and good economic and social benefits.