The invention discloses a biological 
organic fertilizer using orange peel residue as a main 
raw material and a preparation method thereof. The biological 
organic fertilizer comprises the following raw materials in percentage by weight: 65 to 75 percent of orange peel residue, 5 to 8 percent of rice 
husk, 4 to 5 percent of wood dust, 0 to 5 percent of 
stevia rebaudiana filter residue, 10 to 20 percent of animal 
manure, and 1 to 2 percent of micro 
fertilizer and biological strains. The biological 
organic fertilizer is prepared by the steps of orange peel residue pretreatment, proportioning, primary degradation, 
compost ageing treatment, adding of biological functional 
bacteria at the rear end and the like. Various indexes of the biological organic 
fertilizer prepared by the method are totally superior to the biological organic 
fertilizer standards issued by the state; after the biological organic fertilizer is applied to the soil, the water, fertilizer, gas and heat conditions of the soil can be effectively improved, so that the soil becomes loose and fertile and is favorable for cultivation and growth and development of 
crop roots, the yield is increased, and the product quality is improved; the biological organic fertilizer is particularly suitable to be used as a special biological organic fertilizer for 
navel orange; and the 
industrial waste residue of 
orange juice is changed into valuable, the environment is protected, the comprehensive benefit is improved, and the invention has good economic benefit and ecological benefit.