Abstract: A new process for preparation of high-quality potassium dihydrogen phosphate（KDP） by organic solvent extraction method with wet-process phosphoric acid and potassium chloride as raw materials was developed.The influences of the addition amounts of potassium chloride on defluorination in the dissolution process were analyzed，and the influences of extraction temperature，extraction time，phase ratio，and the amount-of-substance ratio of phosphoric acid to potassium chloride etc.on the extraction rates of H₃PO₄ and HCl，as well as on the removal rates of SO₄²⁺，Fe³⁺，and F^- etc.were analyzed.According to the influences of phase ratio on washing rate of P₂O₅，the suitable technological conditions were confirmed.Results showed that when the extraction temperature was 60 ℃；extraction time was 30 min；phase ratio was 3.0；amount-of-substance ratio of potassium chloride  to phosphoric acid was 1.0；and phase ratio of washing was 12，P₂O₅ yield could reach over 95.98% and the purity of product KDP was more than 96.75%.

Key words: wet-process phosphoric acid, solvent extraction, potassium dihydrogen phosphate（KDP）, potassium chloride