NOVELTY - Preparing biofertilizer by mixing organic fertilizer and residues left out after oil extraction from rapeseeds, adding purified water, Bacillus subtilis, Lactobacillus and B.mucilaginosus to mixture, stirring mixture, stacking mixed material, detecting internal temperature of stacks, turning the stacks, air-drying stacks, cooling dried stacks, turning stacks, fermenting stacked materials, spreading fermented product, turning fermented product, allowing fermented product to dry naturally, and detecting water content of fermented product.    USE - The method is useful for preparing biofertilizer for apple (claimed).    ADVANTAGE - The method is environmentally-friendly, and enables preparation of biofertilizer that does not deteriorate roots of apple trees, and enables to cultivate apples having improved quality when compared to apples that are cultivated using existing chemical fertilizers.    DETAILED DESCRIPTION - Method for preparing biofertilizer, involves (a) mixing organic fertilizer and residues left out after oil extraction from rapeseeds uniformly in a respective mass ratio of 7:3, adding purified water to obtained mixture in a volume ratio of 50-60:100, further sequentially adding Bacillus subtilis, Lactobacillus and B.mucilaginosus to the mixture, and stirring mixture uniformly to obtain mixed material, (b) stacking the mixed material into strip shaped stacks having height of 20-50 cm and width of 100-120 cm, and detecting internal temperature of the stacks until internal temperature reaches 35 degrees C, (c) turning the stacks when internal temperature reaches 35 degrees C, air-drying stacks, cooling dried stacks, turning the stacks continuously once every day for 3-5 days, and fermenting stacked materials, (d) spreading fermented product up to a thickness of 15-25 cm when temperature of the fermented product is not increasing and stable at 25-28 degrees C, turning the fermented product once a day, and allowing the fermented product to dry naturally, and (e) detecting water content of the fermented product, and obtaining biofertilizer when water content is reduced to 28-30%.