The invention relates to a preparation method for a highly-water-soluble trace-element-containing pesticide-embedded type ammonium polyphosphate-potassium sulfate pesticide-fertilizer integrated agricultural chemical. The invention solves the technical problems of improving the content of trace elements in a conventional fertilizer, embedding an organic pesticide into ammonium polyphosphate molecules, and realizing pesticide-fertilizer integration. The preparation method comprises the following reaction processes: adding phosphoric acid with a concentration of 85%, ammonium dihydrogen phosphate, urea, potassium sulfate and a trace element nitrate into a reaction kettle according to a certain mass proportion, carrying out mixing and dissolving in the reaction kettle, and carrying out uniform mixing under stirring; heating the reaction kettle to 110 DEG C under stirring, carrying out a reaction for 5 minutes, carrying out heating to 120 DEG C, and carrying out a reaction for 10 minutes; and after completion of the reaction, allowing the temperature in the reaction kettle to be gradually decreased to 40 DEG C, adding 0.5 mol/L of a pesticide (an insecticide or a herbicide) into a sample, carrying out stirring for 5 minutes, and allowing a diluted phosphoric acid solution to absorb ammonia gas generated by the reaction at the same time so as to be able to obtain a product provided by the invention.