NOVELTY - Organic-inorganic compound fertilizer comprises sludge after sewage treatment, ash, watermelon, dairy manure, bagasse, egg, oil cake, tree ash, phosphogypsum, poultry feather, monoammonium phosphate, superphosphate, potassium chloride, carboxymethyl chitosan, modified bentonite, coal, Clover, Celastrus angulatus, herba artemisiae capillaris, fructus cnidii, Quisqualis, wormwood, Litsea cubeba, pollen, paraffin, zinc sulfate, ferrous sulfate, borax, potassium fulvate, chili oil, and effective microorganism (EM) strain.    USE - The organic-inorganic compound fertilizer is useful for providing insecticidal effect.    ADVANTAGE - The fertilizer improves watermelon quality and yield, provides nutrient to watermelon to develop green leaves and bright flower, and prolongs flowering period.    DETAILED DESCRIPTION - Organic-inorganic compound fertilizer comprises 50-70 pts. wt. sludge after sewage treatment, 20-30 pts. wt. ash, 30-40 pts. wt. watermelon, 20-30 pts. wt. dairy manure, 15-20 pts. wt. bagasse, 5-7 pts. wt. egg, 8-10 pts. wt. oil cake, 10-15 pts. wt. tree ash, 10-15 pts. wt. phosphogypsum, 8-10 pts. wt. poultry feather, 8-10 pts. wt. monoammonium phosphate, 10-12 pts. wt. superphosphate, 12-15 pts. wt. potassium chloride, carboxymethyl chitosan, 20-30 pts. wt. modified bentonite, 10-12 pts. wt. coal, 2-4 pts. wt. Clover, 9-11 pts. wt. Celastrus angulatus, 8-10 pts. wt. herba artemisiae capillaris, 5-7 pts. wt. fructus cnidii, 6-8 pts. wt. Quisqualis, 3-5 pts. wt. wormwood, 3-5 pts. wt. Litsea cubeba, 8-10 pts. wt. pollen, 3-5 pts. wt. paraffin, 1-1.25 pts. wt. zinc sulfate, 2-3 pts. wt. ferrous sulfate, 0.8-1.2 borax, 10-12 pts. wt. potassium fulvate, 3-4 pts. wt. chili oil, and 0.2-0.5 pts. wt. effective microorganism (EM) strain. An INDEPENDENT CLAIM is included for method for preparing the organic-inorganic compound fertilizer, which involves (a) soaking C.angulatus, herba artemisiae capillaris, fructus cnidii, Quisqualis, wormwood and L.cubeba in water, and extracting soaked materials, concentrating extract to obtain Chinese medicinal herbal concentrated solution, (b) weighing the materials chosen from sludge, ash, dairy manure, oil cake, baggase, tree ash and phosphogypsum, adding water to the materials, fully mixing the materials, adding EM strain, mixing them uniformly, and adjusting the pH to 5.5-6.5, (c) fermenting the mixture for 8-10 days at 45-55 degrees C, where for every 2-3 days mixing the fermented material, and continuing fermentation for 10-15 days at 60-65 degrees C to obtain fermented organic substance, (d) adding poultry feather to 25-35% hydrochloric acid and hydrolyzing for 8-9 hours to obtain amino acid, then adding lime to neutralize the amino acid, adding carboxymethyl chitosan, zinc sulfate, ferrous sulfate and borax to amino acid, and dissolving added materials to obtain amino acid chelate, (e) adding bentonite, sodium hydroxide solution and deionized water to the chelate, then adding sodium lauryl sulfate, tribute phosphate and aluminum hydroxide, mixing added materials at high speed of 1000-1200 revolution/minutes (rpm), stirring materials, and drying the materials, grinding the materials into fine powder to obtain modified bentonite, (f) burning phosphate slag at 6-8 degrees C for 400-500 hours, grinding it into powder, and adding paraffin to modified bentonite to obtain fertilizer carrier, and (g) mixing monoammonium phosphate, superphosphate and potassium chloride, adequately mixing materials, grinding the materials, mixing traditional Chinese medicine liquid, amino acid chelate, fertilizer liquid, grinded material and fertilizer carrier to obtain mixture, granulating the mixture, and finally spraying chili oil on granulated material.