The invention relates to a process for producing potassium phosphate with wet phosphoric acid. The process comprises the following steps that: 1) wet phosphoric acid is put into an ultrasonic reactor for ultrasonication at the temperature of 2-80 degree centigrade with the reaction time of 10-120 minutes; then the product is cooled to be at room temperature and precipitates are leached, thus obtaining a filter liquor; 2) potassium hydroxide, potassium carbonate or potassium bicarbonate is used to regulate the PH value of the filter liquor and generate precipitates, and a new filter liquor obtained after filtering is concentrated, evaporated, crystallized and then separated, thus obtaining potassium phosphate. The process is characterized in that wet phosphoric acid with low purity, purityand cost, lead-bearing material and potassium chloride are used as raw materials to react and generate potassium phosphate, which reduces production cost. Impurities in the raw materials interact andgenerate insoluble precipitates, and the insoluble precipitates can be easily separated. In the simple process, products are generated only by concentrating and crystallizing a neutralizer; potassiumphosphate is directly prepared by utilizing phosphoric acid with the concentration of 5-40%, which solves the problems of low consistency of wet phosphoric acid and high energy consumption for concentration.