The invention discloses a biological humic acid fertilizer. Edible mushroom residues, apple pomace, soybean molasses, a texturizing agent, compound enzymes and complex microbial inoculants are main raw materials, all the raw materials are subjected to enzymolysis, the product and microorganisms are fermented, and the ciologiacal humic acid fertilizer is prepared. The method includes the special steps that after the mushroom residues are subjected to steam explosion, enzymolysis and fermentation are carried out through the compound enzymes and the complex microbial inoculants, and the conversion rate of biological humic acid is increased. By means of the biological humic acid fertilizer, the comprehensive utilization level of mushroom residues is increased, and the biological humic acid fertilizer has the effects of improving soil, promoting plant growth and improving disease resistance and stress resistance and improving the product quality, and has the remarkable economic benefits and social benefits.