The invention provides a special sweet potato fertilizer. The special sweet potato fertilizer is prepared from the following raw materials in parts by weight: 10-20 parts of vinasse, 15-17 parts of enveloped ammonium bicarbonate, 10-12 parts of monoammonium phosphate, 10-12 parts of enveloped ammonium sulfate, 16-18 parts of enveloped potassium sulphate, 20-30 parts of plant ashes, 1-2 parts of manganese sulfate, 1-2 parts of ferrous sulfate, 1-2 parts of magnesium sulfate, 0.1-0.5 part of zinc sulfate, 0.1-0.3 part of borax, 10-12 parts of cinerite, 5-7 parts of wood charcoals, 3-4 parts of radix euphorbiae lantu powders, 3-4 parts of radix stemonae powders, 10-15 parts of bagasse, 10-15 parts of volcanics, 18-22 parts of cow dung, 3-4 parts of carboxymethylcellulose, 15-20 parts of 30% of sulfuric acid, 5-10 parts of limes, 10-15 parts of pig hairs and 4-6 parts of cottonseed oil. The special sweet potato fertilizer is prepared by a method comprising the following steps: conducting acidolysis on hairs to generate amino acid, then generating a micro element fertilizer liquid and an intermediate element fertilizer liquid chelated with amino acid, then sintering the volcanics to prepare a fertilizer carrier, fermenting an organic fertilizer, mixing a nitrogen-phosphorus-potassium fertilizer, the carrier, the organic fertilizer and a vegetable insecticide, then spraying the micro element fertilizer liquid and the intermediate element fertilizer chelated with amino acid, then granulating, and finally adopting the cottonseed oil for enveloping. According to the special sweet potato fertilizer provided by the invention, the fertilizer utilization ratio is improved obviously, the slow release effect is achieved, the fertilizer application amount is lowered, the pesticide residual is lowered, and the output and the quality of sweet potatoes are improved.