The invention relates to a compound fertilizer, and provides a biochemical compound fertilizer which is characterized by adopting the raw materials with a certain mixture ratio: potassium humic acid,amino acid, weathered coal, phosphoric acid I, diamine and hydrated lime that are processed by grinding, mixing, evenly stirring and pelleting for preparing the biochemical compound fertilizer; the application test proves that the biochemical compound fertilizer can improve the yield and the quality of crops as well as the structure of the soil, and enhance the fertile degree of the soil as well as lodging-resistant, disease-resistant and pest-resistant performances of the crops.