The invention discloses a walnut special-purpose and a preparation method thereof, which belong to the technical field of agricultural fertilizer. The foliar fertilizer comprises the following components: composite amino acid powder, daminozide, triacontanol, compound sodium nitrophenolate, disodium ethylene diamine tetraacetate, calcium nitrate, potassium dihydrogen phosphate, magnesium sulfate, manganese sulfate, copper sulphate, ferrous sulphate, ammonium molybdate, boric acid, white copperas zinc sulfate and deionized water. The walnut foliar fertilizer contains abundant nutrient element, and provides good nutrient base for growth and fructification of walnut tree, and has the advantages of fast absorption, good fertilizer efficiency and high fertilizer utilization rate; and is capable of increasing fructification rate, enhancing cold resistance and drought resistance capability, increasing yield and improving walnut quality; the fertilization method is simple, operationality is strong, economic benefit is obvious, orchard worker can be helped for market occupation, and income can be increased.