NOVELTY - Preparing tricalcium phosphate byproduct special fertilizer for rye, comprises (a) preparing intermediate slurry by adding phosphoric acid and carbamide into a kettle, and stirring to obtain an intermediate slurry, (b) synthesizing tricalcium phosphate slurry by adding carbamide and calcium hydroxide into the intermediate slurry to obtain tricalcium phosphate, (c) preparing special fertilizer for rye by adding potassium element and trace element to the filtrate and stirring the reaction solution to obtain concentrated slurry, and (d) drying and granulating to obtain fertilizer.    USE - The method is useful for preparing tricalcium phosphate byproduct special fertilizer for rye.    ADVANTAGE - The method: avoids the discharge of waste liquid; and is carried out in a cost efficient and environmental friendly manner.    DETAILED DESCRIPTION - Preparing tricalcium phosphate byproduct special fertilizer for rye, comprises (a) preparing intermediate slurry by adding phosphoric acid and carbamide in a molar ratio of 1.7-2.3:1 into a kettle and stirring at 110-120 degrees C with a speed of 45-60 revolutions/minute and stirring after reaction for 30-70 minutes to obtain intermediate slurry, (b) synthesizing tricalcium phosphate slurry by adding carbamide and calcium hydroxide solution in a molar ratio of1.2-1.7 into the intermediate slurry at 70-90 degrees C, detecting the pH value until the pH value reaches to 8-9 after 30-70 minutes of the reaction and terminating the reaction, cooling in crystallizer and lowering the temperature to not less than 45 degrees C to obtain tricalcium phosphate crystals, detecting the content of nitrogen and phosphorus, when the content ratio of nitrogen, calcium and phosphorus is (0.4-0.7):(1.1-1.4):(0.3-0.5), terminating the crystallization and centrifuging to obtain a filter cake as tricalcium phosphate product and tricalcium phosphate product at a temperature of 90 degrees C environment, drying to a moisture content of 8-10% to obtain the product with a purity of 97.1-98.3%, (c) preparing special fertilizer for rye by adding potassium element and other trace element to the filtrate obtained in the step (b) until the content of nitrogen, phosphorus and potassium element in filter liquid is (0.4-0.5):(0.9-1.1):(1.1-1.3) and stirring the reaction solution at stirring speed of 50-60 revolutions/minute, maintaining the reaction temperature at 100-110 degrees C after completion of reaction, concentrating and drying to a moisture content of 20-24% and terminating the concentration to obtain concentrated slurry, (d) drying and granulating by adding concentrated slurry into the granulator, spraying the layer of urea formaldehyde slurry to the surface, drying in a dryer at a 70-90 degrees C to a moisture content of 1-3% after spraying a slurry of particles, sterilizing and packaging the special fertilizer.