The invention provides a high-content bacterium-coated biological fertilizer and solves the problems that the existing biological fertilizer is low in content of organic matters and low in content of beneficial bacteria, the growth requirements of plants cannot be met, and the content of heavy metals exceeds the standard. The high-content bacterium-coated biological fertilizer is prepared from the following raw materials: furfural residue, humic acid, kiln dust, bacillus subtilis, bacillus licheniformis, bacillus mucilaginosus, zinc sulphate monohydrate and boric acid. A preparation method of the high-content bacterium-coated biological fertilizer comprises the following steps: firstly mixing the furfural residue and humic acid, fermenting and decomposing, then adding the kiln dust and microelements and stirring, then pelleting and drying, and finally coating and filling to obtain the high-content bacterium-coated biological fertilizer. The high-content bacterium-coated biological fertilizer has the effects of increasing yield and efficiency, improving soil hardness, inhibiting diseases and insect pests, reducing application quantities of chemical fertilizers and accelerating growth of the plants; when the high-content bacterium-coated biological fertilizer is applied to fruit trees, the fruit trees can bloom regular flowers, the flowers and the fruits can be retained, and the leaf fall period is late; the high-content bacterium-coated biological fertilizer is capable of resisting early spring diseases, preventing and treating premature senescence, resisting lodging, resisting drought and cold and reducing pollution to the environment; the content of the bacteria in the biological fertilizer produced by the method reaches one billion per gram; the content of the organic matters in the biological fertilizer reaches up to 80%.