NOVELTY - Preparation of compound fertilizer involves sequentially adding urea, ammonium sulfate, ammonium hydrogen carbonate, monoammonium phosphate, potassium sulfate and calcium superphosphate to a stirrer, mixing, crushing, pelletizing the resultant material, polishing, obtaining particles with particle size of less than 6 mm, drying, cooling, removing dust from the resultant particles, sieving, polishing resultant particles, providing resultant product into a stainless steel spray tube, inspecting resultant product, and obtaining nitrogen, phosphorus and potassium fertilizer.    USE - Preparation of compound fertilizer (claimed).    ADVANTAGE - The method enables simple and economical preparation of environmentally-friendly compound fertilizer with reduced energy consumption and excellent pelletizing effect.    DETAILED DESCRIPTION - Preparation of compound fertilizer involves sequentially adding urea, ammonium sulfate, ammonium hydrogen carbonate, monoammonium phosphate, potassium sulfate and calcium superphosphate to a stirrer, mixing for 0.5-4 minutes, crushing resultant mixed material by double-disc grinder by rough crushing and fine crushing, pelletizing the resultant material in a mixing and pelletizing region, polishing resultant particles in a particle polishing region, obtaining particles with particle size of less than 6 mm, drying by dryer, cooling to 100-170 degrees C, removing dust from the resultant particles, drying at 150-220 degrees C, cooling to 50-80 degrees C, controlling moisture content of discharge material to 5-8%, sieving to remove particles having particle diameter of more than 4.75 mm, grinding sieving out particles of having particle diameter of less than 2 mm, polishing resultant particles, providing resultant product into a stainless steel spray tube having diameter of 15 mm, inspecting resultant product, and obtaining nitrogen, phosphorus and potassium fertilizer. INDEPENDENT CLAIMS are included for the following:    (1) rotary drum pelletizer;    (2) dryer; and    (3) cooler.