The invention relates to a method for the 
combined test of 
total nitrogen and total 
phosphor phosphorus in soil, which comprises the following steps: (1) synchronous 
digestion treatment of soil: weighing a dried and screen soil sample, placing the sample into a 
digestion tube, adding an accelerator, adding solution of concentrated 
sulfuric acid and placing the 
digestion tube in at high-temperatureenvironment for digestion; (2) preparation of soil liquid to be tested: after the digestion liquid obtained after digestion is cool, fixing the volume of the digestion liquid by adding 
distilled water, using the digestion liquid to test the 
total nitrogen content of the soil, adjusting the pH value of soil 
total nitrogen liquid to be tested by using alkaline liquid and using the resulting liquidto test the total 
phosphor content of the soil; and (3) test of the total 
nitrogen content and total 
phosphor content of soil: automatically testing the total 
nitrogen content and total phosphor content of soil by using a constant flow injection analyzer. The method has the advantages of: 1, avoiding repeated soil sample weighing and soil digestion and simplifying experimental operation process; 2, avoiding damages of 
selenium powder to human bodies by using 
potassium sulfate and 
copper sulfate in place of the accelerator for soil 
digestion treatment; and 3, improving 
accuracy and precision bytesting total 
nitrogen content and total phosphor content of soil by using constant flow injection analyzer.