NOVELTY - Preparing rice bio-fertilizer involves adding Bacillus subtilis with preservation number (CGMCC No.6190) to solid material, and fermenting until the number of Bacillus subtilis reaches at least 1.2x 1010 per g, and spore rate reaches at least 60%, to obtain fermented solid material containing e.g. rice hull powder and magnesium sulfate; and performing composting fermentation of the material, humic acid, agricultural rare earth, livestock excrement, and silicon-calcium-magnesium fertilizer, and then mixing uniformly amino acid fertilizer to obtain rice bio-fertilizer.    USE - For preparation of rice bio-fertilizer (claimed), used in agricultural production.    ADVANTAGE - The process improves tillering number of the rice; increases rice root weight; provides rice good growth state under cold stress; improves content of amylose in rice water; and requires short production period.    DETAILED DESCRIPTION - Preparation of rice bio-fertilizer involves adding Bacillus subtilis with preservation number (CGMCC No.6190) to the solid material, and fermenting until the number of Bacillus subtilis reaches at least 11.2x 1010 per g, and Bacillus subtilis spore rate reaches at least 60%, competitor of less than 20%, to obtain the fermented solid material containing rice hull powder or peanut shell powder (35-45 parts by weight (pbw)), wheat bran (45-55 pbw), soybean cake powder (4-6 pbw), corn powder (4-6 pbw), and magnesium sulfate (o.o4-0.06 pbw) containing solid mixture (0.005-0.015 pbw) and water; and performing composting fermentation of the solid fermentation material (5 pbw), humic acid (7.7 pbw), agricultural rare earth (0.3 pbw), livestock excrement 30-75), and silicon-calcium-magnesium fertilizer (5 pbw), and then mixing uniformly amino acid fertilizer (5 pbw) to obtain the rice bio-fertilizer. The process further involves adding nitrogen-phosphorus-potassium fertilizer for mixing uniformly. An INDEPENDENT CLAIM is included for new Bacillus subtilis with preservation number (CGMCC No.6190).