Abstract: <DIV>The contents of nitrogen and chlorine in the production of potassium dihydrogen phosphate (KDP) with ammonium dihydrogen phosphate and potassium chloride should be measured frequently，but routine analysis method takes long time and the test conditions should be strictly controlled.In this respect，a new method that can rapidly determine the contents of nitrogen and phosphorus of the product has been established by combining the formaldehyde method for nitrogen with acid-base titration method for phosphorus.Moreover，by contrasting with standard analytical methods (titration method after distillation and the quinoline phosphomolybdate gravimetric method)，the accuracy of this analytical method was evaluated.The experimental results showed that this analytical method not only is of high accuracy，economical and rapid，but also apt to control analytical conditions.</DIV>