The invention discloses a nutrient solution formula, a nutrient solution preparation method and a nutrient solution preparation device. The formula comprises calcium nitrate, ferrous sulfate, purified water, magnesium sulfate, sodium sulfate, potassium nitrate, copper sulfate, zinc sulfate, plant ash powder, calcium superphosphate, potassium sulfate, ammonium dihydrogen phosphate, sodium chloride, boric acid, auxin, EDTA calcium, calcium acetate, high-activity humic acid, EDTA manganese, EDTA iron, earthworm liquid, calcium superphosphate extract, sodium hydroxide, wollastonite, gypsum, white mud, dolomite, urea, industrial monoammonium phosphate, hydrochloric acid and deionized water. The preparation method comprises the following steps of S1, crushing the raw materials, S2, mixing the basic liquid, S3, mixing for the first time, and S4, mixing for the second time. The preparation device comprises a first treatment tank, a first supporting table and a second supporting table are arranged on the left side and the right side of the first treatment tank respectively, a second treatment tank is arranged on the surface of the first supporting table, and a third treatment tank is arranged on the surface of the second supporting table.