NOVELTY - Method for preparing bio-organic fertilizer, involves mixing manure, straw and effective microorganism, adding water, fermenting mixture, adding e.g. nano kaolin and egg white powder, fermenting mixture, dewatering pre-fermented material, adding VT microbe, fermenting mixture, performing secondary fermentation, adding e.g. straw ash, mixing, aging mixture, dewatering, granulating mixture, and performing drying to obtain fertilizer.    USE - The method is useful for preparing bio-organic fertilizer (claimed).    ADVANTAGE - The method is simple.    DETAILED DESCRIPTION - Method for preparing bio-organic fertilizer, involves (a) adding 40-80 pts. wt. manure, 30-40 pts. wt. straw and 1-3 pts. wt. effective microorganism into a fermenting tank, adding 40-55 wt.% water, mixing uniformly, fermenting mixture at 25-35 degrees C for 100-120 hours (turning mixture once for every 10-12 hours), adding 30-60 pts. wt. nano kaolin, 5-15 pts. wt. diatomite, 10-20 pts. wt. zeolite powder, 5-15 pts. wt. fishbone meal, 10-18 pts. wt. traditional Chinese medicinal residue, 20-35 pts. wt. effective microorganism and 10-25 pts. wt. egg white powder, fermenting mixture for 40-70 hours (turning mixture once for every 5-10 hours) to obtain pre-fermented material, (b) dewatering pre-fermented material, adding 0.5-2 pts. wt. VT microbe, fermenting mixture at 60-75 degrees C for 5-10 days (turning mixture once for every 20-35 hours), and introducing air to aerate the fermented material to obtain primary fermented material, (c) stacking primary fermented material, performing secondary fermentation for 10-15 days (turning mixture once for every 1-2 days), adding 10-25 pts. wt. straw ash, 5-15 pts. wt. nano bentonite, 5-12 pts. wt. nano carbon powder, 10-16 pts. wt. sodium carboxymethyl cellulose and 5-15 pts. wt. sepiolite, mixing uniformly, and aging mixture for 5-10 days and dewatering to obtain secondary fermented material, and (d) granulating mixture, spraying amino acid hydrolyzate before granulating, and performing drying to obtain fertilizer.