The invention relates to an organic-inorganic set fertilizer for the quality improvement and effect enhancement of tea and a preparation method thereof. The set fertilizer comprises base fertilizer and topdressing fertilizer; the base fertilizer is prepared by fermenting farmyard manure, brewer's grain, tea residues, Chinese herbal residues, tea tree fallen leaves, straw powder, soybean meal powder, peat soil, earthworm excrement, edible fungus residue, mashed grape, mashed apple, mashed lemon, silkworm excrement, medical stone powder, biological charcoal residues, plant ash, lime powder, borax, proteolytic enzymes, lactic acid bacteria, azotobacter, rhizobium, potassium-dissolving bacteria, cellulose-decomposing bacteria, antibiotic-producing bacteria and rice washing water; the topdressing fertilizer is prepared by mixing fulvic acid, urea, sodium humate, potassium chloride, ferrous sulfate, zinc chloride, calcium superphosphate and water. The preparation method of the organic-inorganic set fertilizer comprises the steps of preparing the base fertilizer and preparing the topdressing fertilizer; the set fertilizer can enhance the fertilizer maintenance and water retention capabilities of soil, provide more abundant and easily-absorbed nutrients for tea growth and improve the quality and yield of the tea; the preparation method is easy to operate, and the raw materials can be fermented and decomposed more completely.