A phosphogypsum desulfurization calcining treatment system and method are included. the phosphogypsum desulfurization calcining treatment system comprises a low temperature dehydration system, a hightemperature calcination system and an acid making system, the low temperature dehydration system sequentially comprises a dryer, a drying mill and a pipeline furnace, the high temperature calcinationsystem sequentially comprises a preheating device, a rotary kiln and a cooler, natural water and crystal water are removed from phosphogypsum through low-temperature drying and high-temperature grinding and drying to obtain anhydrous gypsum, high-temperature calcination is carried out on the anhydrous gypsum, air cooling is carried out, the calcined anhydrous gypsum is sent to a cement productionline as a cement raw material, and gas generated in the calcination process is collected, and then sent to an acid making system to prepare sulfuric acid. According to the invention, a phosphogypsum acid making system and a cement system are separated, phosphogypsum dehydration, phosphogypsum decomposition, kiln gas acid making and resource comprehensive utilization of kiln slag are included, so that mutual interference between a desulfurization process and a cement process can be reduced, production of high-quality Portland cement and high-quality sulfuric acid is ensured, and harmless, resource and large-batch treatment of phosphogypsum is realized.