The invention discloses a preparation method of a broccoli compound fertilizer with a characteristic of utilization rate improving. The preparation method comprises: uniformly mixing and stirring gum arabic and an ethanol solution, adding sodium hydroxide, carrying out heating stirring, adding 2-chloroethanol, stirring, adding maleic anhydride, continuously stirring, adjusting the pH value of the system to 6-6.8 with hydrochloric acid, adding starch, stirring, adding lauric acid, uniformly mixing, conveying into an extruder, extruding, heating, carrying out thermal insulation, and crushing to obtain a first preform; uniformly mixing corn cob powder, pine needle powder, coptis chinensis residue and an EM bacterial liquid, crushing, fermenting, carrying out high temperature sterilization, cooling, and carrying out air drying to obtain a second preform; and uniformly mixing potassium nitrate, calcium superphosphate, potassium dihydrogen phosphate, ammonium nitrate, magnesium humate, zinc humate, borax and iron humate, adding the first preform and the second preform, and uniformly stirring to obtain the broccoli compound fertilizer. According to the present invention, the broccoli compound fertilizer does not contain heavy metal pollutants, the preparation method is simple, and the obtained broccoli compound fertilizer meets the broccoli growth requirements.