The invention discloses a bio-organic fertilizer. The bio-organic fertilizer is composed of, by weight, 30-40 parts of cassava residues, 15-20 parts of ammonium bicarbonate, 2-5 parts of indigowoad leaf powder, 3-4 parts of alum powder, 6-8 parts of plant ash, 4-5 parts of flour, 4-5 parts of grass meal, 10-15 parts of brown sugar,1-2 parts of vegetable oil, 6-8 parts of bamboo leaf powder, 5-20 parts of unite bran, 4-6 parts of citric acid residues, 50-60 parts of swill, 10-15 parts of sawdust, 4-6 parts of sweet clover powder and 25-40 parts of faeces of human and animals. The bio-organic fertilizer produced by the method has high organic matter content, and can improve soil quality and soil structure, thereby keeping ecological balance. Besides, the bio-organic fertilizer is comprehensive in nutrition and contains macroelements and microelements required by crops and a large amount of active substances produced during a microbial fermentation process.