The invention belongs to the technical field of fertilizers, and relates to a potato polymerization special fertilizer and a preparation method thereof, the special fertilizer is prepared by mixing, heating polymerization, drying and crushing raw materials comprising a water-absorbent polymer monomer, inorganic nutrients, a catalyst, a cross-linking agent and an initiator; the inorganic nutrients comprise nitrogen fertilizer, phosphate, potassium salt, silicate, calcium salt, magnesium salt, ferric salt, borate, copper salt, molybdate, manganese salt and zinc salt; the potatoes planted by using the special polymerized fertilizer are rich in mineral substances, amino acids and trace elements, the balanced uptake of nutrient elements by a human body is met, the nutrition and health of the human body are ensured, and the special polymerized fertilizer is simple in preparation method, low in production cost, labor-saving, time-saving, energy-saving, environment-friendly, non-toxic, harmless, residue-free, completely degradable, non-volatile, non-explosive, non-combustible, insoluble in water and suitable for popularization and application. Long-term effectiveness is realized; the quality is safe and reliable; and the market prospect is wide.