NOVELTY - Bio-organic composite fertilizer composition comprises (in pts.wt.): cassava residue (45-50), sugar (47-52), furfural (36-41), bentonite (8-10), ferrous sulfate (2-3), bamboo charcoal powder (10-12), sepiolite powder (7-10), alkyl polyglycosides (3-5), sodium humate (3-5), urea (26-29), monoammonium phosphate (17-19), potassium sulfate (15-18), EM (RTM: Effective microorganism) (5-7), soil improving agent (7-9) and balanced amount of water.    USE - Bio-organic composite fertilizer composition.    ADVANTAGE - The bio-organic composite fertilizer composition shows synergistic effect, improved nutrition absorbing property and soil plate structure, and shows improved sustained release effect of fertilizer.    DETAILED DESCRIPTION - Bio-organic composite fertilizer composition comprises (in pts.wt.): cassava residue (45-50), sugar (47-52), furfural (36-41), bentonite (8-10), ferrous sulfate (2-3), bamboo charcoal powder (10-12), sepiolite powder (7-10), alkyl polyglycosides (3-5), sodium humate (3-5), urea (26-29), monoammonium phosphate (17-19), potassium sulfate (15-18), EM (RTM: Effective microorganism) (5-7), soil improving agent (7-9) and balanced amount of water. Soil modifying agent comprises (in pts.wt.): alkyd resin (10-20), nano-carbon powder (1-2), sodium silicate (4-5), methyl methacrylate (17-19), selenium yeast (3-4), copper sulfate (2-3), zinc gluconate (2-3), magnesium chloride (1-2), ammonium citrate (2-3), boric acid (1-2), dipentaerythritol hexaacrylate (4-6), vinegar (30-40), chitosan (2-3), Eucalyptus oil (1-2), tripropylene glycol diacrylate (3-5), alum (5-6) and iron ore slag (1-2). Soil modifying agent is prepared by mixing and heating methyl methacrylate, dipentaerythritol hexaacrylate, tripropylene glycol diacrylate, alkyd resin, nano-carbon powder, Eucalyptus oil and iron ore slag at 65-75 degrees C. The remaining component is added to the obtained material with stirring to obtain soil modifying agent. An INDEPENDENT CLAIM is included for a method for preparing bio-organic composite fertilizer composition, which involves:    (A) mixing ferrous sulfate, sodium humate, monoammonium phosphate and potassium sulfate in water;    (B) adding soil, bentonite, sepiolite powder and alkyl polyglycosides to the obtained material with stirring,and then drying them to prepare granule;    (C) adding urea to the obtained material, and then fermenting them for 22-30 days; and    (D) cooling the obtained material, and then drying to obtain the finished product.