The invention discloses a compound fertilizer, which consists of the following raw materials: 6 percent of fulvic acid, 0.5 percent of magnesium sulfate, 0.5 percent of ferrous sulfate, 1 percent of zinc sulfate, 2 percent of ammonium sulfate, 0.5 percent of manganese sulfate, 0.2 percent of ammonium molybdate, 1.2 percent of borax, 6 percent of superphosphate, 25 percent of polypeptide urea and 15 percent of potassium sulfate. The compound fertilizer has the advantages of adjusting too low or too high soil acidity or alkalinity, resisting salinity and alkalinity, improving hardened soil, promoting the growth of crops, improving disease-resistant capacity of the crops, resisting lodging, resisting continuous cropping, resisting plant diseases and insect pests, resisting freeze injury, protecting soil against water loss, improving drought resistance capacity, improving the yield of the crops, improving the quality of the crops, vegetables, melons and fruits, improving the original quality and taste of the vegetables, melons and fruits, and prolonging the refreshing time thereof.