NOVELTY - Preparing sulfur ammonium phosphate product from phosphorus gypsum involves: using phosphoric acid phosphogypsum device, synthetic ammonia device of carbon dioxide and ammonia synthesis reaction to generate sulfur ammonium phosphate slurry, purifying raffinate and producing synthetic ammonia by wet-process phosphoric acid reaction to produce ammonium phosphate slurry, mixing the two slurries to certain proportion, adding proper non-polluted nutrient agent, pelleting/drying using granulation, crushing to obtain semifinished product and sieving and washing.    USE - For preparation of sulfur ammonium phosphate product from phosphorus gypsum (claimed).    ADVANTAGE - The prepared sulfur ammonium phosphate product has quality index of nitrogen of not less than 13%, P2O5 of 34%, S of 6%, H2O of 2%, and at 2.4 mm, has compressive strength of 90% with 30% nitrogen and SGN is not less than 280. The method uses ammonium sulfate slurry producing sulfur phosphorus ammonium and ammonium phosphate slurry, provides stable nutrient product, uniform, with high compressive strength, greatly reduces the enterprise environmental protection caused by pressure, and cost.    DETAILED DESCRIPTION - Preparation of sulfur ammonium phosphate product from phosphorus gypsum involves: preparing materials by phosphoric acid device, synthetic ammonia device of carbon dioxide and ammonia synthesis reaction to generate ammonium sulfate slurry; purifying raffinate and producing synthetic ammonia by wetprocess phosphoric acid reaction to produce ammonium phosphate slurry; mixing the two slurries using stirrer in an accurate proportion by the flow meter, and adding nutrient agent according to the actual requirement; raising the temperature of slurry circulating system and mixing the slurry, heating the slurry to 85-100 degrees C; pelleting/drying the prepared slurry into spray granulation and drying using heat source as fire coal furnace in fluid bed which is a flue gas of 550-600 degrees C generated by the high temperature gas to spray slurry and drying, tail gas by the tail gas draught fan by the cyclone dust collector to the syringe, a gas dust-removing standard empty through the exhaust tube into the venture; crushing and sieving the obtained product and drying bucket elevator through the semi-finished product and sieving semi-finished product to obtain sieve; cooling and covered by sieving, 2-4 particles from entering the cooling cylinders, according to the need, and covered to obtain sulfur ammonium phosphate product, more than 4 mm particle by returning crushing machine, crushing and sieving the 1-2 mm particles as returning to pelleting/drying machine.