The invention discloses a method for producing organic fertilizer from biological wastes. The method comprises five steps: pre-treating five raw materials, i.e. livestock manure, mud, agricultural wastes such as crop straws, fungus residues and microbial inoculum, mixing the raw materials, stacking and fermenting the raw materials, secondarily fermenting the mixture, forming the organic fertilizer, and packing and warehousing the organic fertilizer. By adopting the method, the livestock manure and the organic matter sludge can be harmlessly treated and reduced, so that the effective utilization, circulating utilization and recycling of organic matters can be realized; on one hand, plant nutrients including necessary macroelements such as nitrogen, phosphorus, potassium, calcium, magnesium,sulfur and trace elements such as iron, manganese, boron, zinc, molybdenum, copper and the like are provided, and organic nutrients such as amino acids, amide, nucleic acid and the like and active substances such as vitamin B1, vitamin B6 and the like are contained, and on the other hand, the effectiveness of the soil nutrient can be improved, the animal fertilizer contains a great amount of microorganisms and various enzymes, so that organic nitrogen and phosphorus can be changed into inorganic state to be absorbed by crops.