The invention relates to a biological organic fertilizer which is prepared from the following raw materials in parts by weight: 0.5 part of Bacillus amyloliquefaciens, 0.5 part of Bacillus mucilaginosus, 35-50 parts of fermented chicken manure, 15-25 parts of fermented cattle manure, 15-20 parts of fermented mushroom residue and 19 parts of medical stone. Every part of medical stone contains 66.88% of silicon oxide, 17.17% of aluminum oxide, 4.24% of potassium oxide, 1.59% of sodium oxide, 1% of magnesium oxide, 1.17% of calcium oxide, 2.66% of iron oxide, 0.37% of titanium oxide and 0.09% of manganese oxide. The effective viable count of the Bacillus amyloliquefaciens and Bacillus mucilaginosus is at least 20 million/g, and the content of the organic matters, including the fermented chicken manure, cattle manure and mushroom residue, is greater than 40.0% of the total nutrients. The effective viable bacteria contained in the biological organic fertilizer can solve the problem of various diseases caused by fungi, bacteria and viruses in the soil, can implement phosphate solubilization, potassium solubilization and nitrogen fixation, and reduce the application amount of large chemical fertilizers. The biological organic fertilizer contains abundant organic matters, and thus, is capable of improving the soil, activating the soil, eliminating soil hardening and enhancing the water storage and fertilizer retention capacities of the soil.