NOVELTY - Water-soluble fertilizer comprises weathered coal, lignite, peat or turf, nitric acid, ammonia water, waste liquid of amino acid fermentation, water-soluble nitrogen fertilizer, water-soluble phosphate fertilizer, water-soluble potash fertilizer and microelement, where the particle size of weathered coal, lignite and peat or turf is 100-200 meshes, and the humic acid content is greater than or equal to 50%. The waste liquid of amino acid fermentation is prepared industrially by using grain crops as raw material, performing microbial fermentation, and separating the fermented waste.    USE - As water-soluble fertilizer.    ADVANTAGE - The water-soluble fertilizer exhibits synergistic effect, improves soil, is saline-alkali resistant, highly nutritious, cost-effective, environment-friendly as it causes no pollution, and safe as it leaves no residue, and has high content of active organic matter. The method consumes less energy, requires low investment and small floor space, realizes zero discharge of amino acid waste liquid and weathered coal, and fully utilizes waste and hence changes waste into treasure.    DETAILED DESCRIPTION - Water-soluble fertilizer comprises weathered coal, lignite, peat or turf, nitric acid, ammonia water, waste liquid of amino acid fermentation, water-soluble nitrogen fertilizer, water-soluble phosphate fertilizer, water-soluble potash fertilizer and microelement, where the particle size of weathered coal, lignite and peat or turf is 100-200 meshes, and the humic acid content is greater than or equal to 50%. The waste liquid of amino acid fermentation is prepared industrially by using grain crops as raw material, performing microbial fermentation, and separating the fermented waste. The water-soluble nitrogen fertilizer is urea. The water-soluble phosphate fertilizer is industrial grade monoammonium phosphate. The water-soluble potassium fertilizer is potassium sulfate, potassium chloride or potassium nitrate. The microelement is one or more of copper sulfate, borax, zinc sulfate and ferrous sulfate. An INDEPENDENT CLAIM is included for method for preparing water-soluble fertilizer, which involves (a) crushing weathered coal, lignite, peat or turf, adding oxidized nitric acid to the crushed components, adding 15% ammonia water to the mixture, mixing and stirring the mixture, and performing extraction and separation to obtain the active humic acid, (b) obtaining the water liquid of amino acid fermentation as carrier, adding the obtained active humic acid, urea, water-soluble phosphate fertilizer, water-soluble potash fertilizer and microelement, fully stirring the mixture, and uniformly mixing the mixture, (c) adding the mixed liquid obtained in the step (b) to spray dryer, preferably high speed centrifugal atomizer, through a conveying pump, and allowing hot air stream at 180-200 degrees C, where the spraying liquid surface area is greatly increased, the hot air stream is capable of instantaneously evaporating 95-99% of water, and the drying time is only for few seconds to form dry powder, and (d) exhausting waste gas using an exhaust fan, collecting the dry powder using collecting tube, and then packaging the obtained product.