NOVELTY - Preparation of bioorganic fertilizer involves passivating heavy metal in sludge with zeolite, sepiolite and bentonite; adding crushed cellulose and amplified fermentation bacteria, and uniformly mixing; stacking mixed material and aerobically fermenting at 55-70 degrees C for 13-17 days, while turning the stack once every two days; stacking obtained decomposed material and anaerobically digesting for 13-17 days until the mixed material is completely decomposed; and crushing and screening.    USE - Method for preparing bioorganic fertilizer (claimed).    ADVANTAGE - The method is environment-friendly and pollution-free, has low investment, and provides for safe management, reduction and reclamation of sludge. The bioorganic fertilizer integrates the fertilizer effects of organic fertilizer and inorganic fertilizer, and has quick and long lasting effect, and synergistic effect.    DETAILED DESCRIPTION - Preparation of bioorganic fertilizer involves:    (A) adding zeolite (0-1.8 wt.%), sepiolite (0-1.2 wt.%) and bentonite (0-2.4 wt.%) to sludge with moisture content of 75-85% to passivate heavy metal;    (B) adding crushed cellulose (peanut shell, straw, sawdust, or rice husk) and amplified fermentation bacteria to the sludge, and uniformly mixing to obtain mixed material comprising (pts. wt.) sludge (1000), crushed cellulose (180-220) and amplified fermentation bacteria (40-60);    (C) stacking the mixed material, and aerobically fermenting at 55-70 degrees C for 13-17 days, while turning the stack once every two days to ensure that aerobic fermentation is completely processed and the mixed material is completely decomposed, in which the decomposition index includes blackish brown or black raw material, stack temperature of 65-75 degrees C, stack pH of less than 8, water-soluble organic substance content of less than 2.2 g/L, water-soluble organic carbon/organic nitrogen ratio of 5-6, and organic carbon/total organic nitrogen ratio of less than 0.75;    (D) stacking the decomposed material and anaerobically digesting for 13-17 days until the mixed material is completely decomposed, in which the decomposition index includes organic substance content of greater than or equal to 30% (based on dried material), moisture content of less than or equal to 30, effective viable bacterial count of greater than or equal to 2x 107/g material, ascarid egg death rate of greater than or equal to 95%, and fecal coliform of less than or equal to 100/g material; and    (E) crushing and screening decomposed material to obtain fertilizer powder with pH of 5.5-8.5.    An INDEPENDENT CLAIM is included for organic-inorganic composite fertilizer obtained by adding nitrogen (N), phosphorus (P) and potassium (K) additive (11-15 wt.%) to bioorganic fertilizer (89-85 wt.%). The NPK additive is obtained by uniformly mixing N source (urea or thiamine), P source (ammonium phosphate or calcium phosphate) and K source (potassium sulfate or potassium chloride).