NOVELTY - Method (M1) for preparing bio-organic fertilizer involves (a) mixing 60-80 pts. wt. rice bran, 5-15 pts. wt. soybean, 5-15 pts. wt. peanut bran and 5-15 pts. wt. soybean residue uniformly to obtain mixed material, turning the mixed material with inosine mother liquid nutrient solution and laying the mixed material, and (b) adding yeast and fermenting at 50-60 degrees C and adding microorganism nutrient solution and propagating for 10-20 days to obtain organic fertilizer.    USE - The method is useful for preparing bio-organic fertilizer, which is useful for planting Litchi, cabbage, grapefruit and rice (all claimed).    ADVANTAGE - The prepared bio-organic fertilizer has pitch-black and bright appearance, soy fragrance, and 0.05 billion cuf/g or more viable count, 47% or more organic matter content, 25% or less water content, 0.11/g or less fecal coliform count, and 95% roundworm mortality. The method enables to produce clean and odorless fertilizer as it doesn't use animal waste and protects the environment.    DETAILED DESCRIPTION - Method (M1) for preparing bio-organic fertilizer involves (a) mixing 60-80 pts. wt. rice bran, 5-15 pts. wt. soybean, 5-15 pts. wt. peanut bran and 5-15 pts. wt. soybean residue uniformly to obtain mixed material, turning the mixed material with inosine mother liquid nutrient solution and laying the mixed material, and (b) adding yeast and fermenting at 50-60 degrees C and adding microorganism nutrient solution and propagating for 10-20 days to obtain organic fertilizer, where the temperature is maintained to 26-30 degrees C and the microorganism nutrient fluid comprises 0.1-0.3 hundred million cuf/ml phosphorus-decomposing bacteria, 0.1-0.3 hundred million cuf/ml silicate bacteria and 0.1-0.3 hundred million cuf/ml Azotobacter. INDEPENDENT CLAIMS are included for the following: (1) preparation of microorganism nutrient solution by adding B.megaterium, silicate bacteria and Azotobacter sp. to inosine mother liquid nutrient solution and culturing at 20-30 degrees C for 50-60 days, and (2) production of bio-organic fertilizer by the above-mentioned method (M1).