The invention discloses polymorphic nitrogenous fertilizer and a preparation method thereof. The polymorphic nitrogenous fertilizer comprises, by weight, 13-18 parts of urea, 63-65 parts of ammonium sulfate, 13-15 parts of ammonium chloride, 3-4 parts of animal hairs and feathers, 14-16 parts of modified attapulgite, 0.6-0.8 part of zinc sulphate monohydrate, 0.2-0.4 part of micronutrients fertilizer, 3-8 parts of ferrous sulfate, 0.3-0.5 part of nitrogen-fixing bacteria, 2-4 parts of modified nanocarbon, 1-3 parts of fructus cnidii, 5-7 parts of pomegranate tree roots and 9-11 parts of willow leaves. The feathers and the like are hydrolyzed by acid to form amino acid, secondary and trace elements are chelated, carboxymethyl cellulose increases a chelation structure of the secondary and trace elements so as to facilitate effective utilization of the secondary and trace elements, and invalid release of the secondary and trace elements is reduced. The polymorphic nitrogenous fertilizer is suitable for crops of wheat, rice, corn, soybean, rape and the like, can urge the wheat and the rice to turn green rapidly, be much in shooting and longing resistant and enhance chill-proof, drought-resistant and disease and insect resistant capacity, and enables cotton and linen crops to enhance tension and strength of fiber and improve output and quality remarkably.