The invention discloses a humic acid-microorganism composite fertilizer. The humic acid-microorganism composite fertilizer is prepared from the following raw materials in parts by weight: 50-52 parts of mushroom bran, 2-3 parts of humic acid, 4-5 parts of pomace, 4-5 parts of peanut meal, 8-9 parts of volcanic ash, 4-5 parts of sea-foam stone powder, 25-30 parts of attapulgite, 5-5.5 parts of azotobacter chroococcum, 70-72 parts of phosphate buffer solution with pH of 7.0, 5-6 parts of sodium alginate, 4-5 parts of calcium chloride and 2-3 parts of chitosan. The mushroom bran is taken as a microbial carrier, so that more organic matters are provided for strain growth; after the mushroom bran is puffed, the hydroscopicity is enhanced, and a wet living environment is provided for microorganisms; the sodium alginate is adopted for embedding, so that the salt tolerance, acid and alkali tolerance, cold and heat tolerance and drug tolerance of the microorganisms can be enhanced; the chitosan is used for enveloping, so that the defect of low mechanical strength of the sodium alginate is overcome; moreover, through the added humic acid, the soil can be improved, and the crop growth is simulated.