NOVELTY - Preparing organic fertilizer, involves (a) grinding agricultural organic waste, adding water to the waste, and mixing decomposing microbial inoculums and the waste to obtain mixture, (b) decomposing the mixture, (c) adding water in animal manure, mixing decomposing microbial inoculums and the manure to obtain mixture, and performing above-mentioned step (b), and (d) mixing the materials obtained in step (b) and step (c) to obtain mixture, adding e.g. microbial composite bacterial liquid, to the mixture, and pelletizing the obtained product.    USE - The method is useful for preparing organic fertilizer, which is used for preventing nematodes and underground pathogenic bacteria.    ADVANTAGE - The fertilizer is enriched with several microelements and environmentally-friendly, maintains buffering property of soil, improves deficiency symptom of crops, promotes absorption of phosphorus and potassium by plants, and provides good living environment for roots of plant.    DETAILED DESCRIPTION - Method for preparing organic fertilizer, involves (a) grinding agricultural organic waste, adding water to the waste such that water content of the organic waste becomes 40-50 wt.%, and mixing decomposing microbial inoculums and the waste in weight ratio of 1:1500-2500 to obtain mixture, (b) maintaining temperature of the mixture to 55-65 degrees C, decomposing the mixture for 15-20 days, and turning and throwing the mixture once at every two days during decomposing period, where the water content of the material after decomposing is 25-35 wt.% (c) adding water in animal manure such that the water content of the manure becomes 30-50 wt.%, mixing decomposing microbial inoculums and the manure in weight ratio of 1:1500-2500 to obtain mixture, and performing above-mentioned step (b), and (d) mixing the materials obtained in step (b) and step (c) in weight ratio of 10-20:1 to obtain mixture, adding 0.5-5 wt.% of microbial composite bacterial liquid, and chelate micro components to the mixture, adding humus acid to adjust the content of organic substance in mixture to 15-45 wt.%, and pelletizing the obtained product.