NOVELTY - Fertilizer synergistic agent comprises 5-nitroguaiacol sodium, wheat bran, rice bran, cottonseed hull, ammonium nitrate, kaolin, modified phosphate rock powder, attapulgite, and suitable quantity of water, where the modified phosphate rock powder comprises rock phosphate powder, gamma -polyglutamic acid powder, ferrous sulfate, calcium bicarbonate, Bacillus subtilis, silicate inoculant, EDTA chelated copper, manganese of humic acid, black liquor, and corn starch.    USE - The fertilizer synergistic agent is useful for promoting growth (claimed), reproduction, and flow of protoplasm in rapeseed.    ADVANTAGE - The fertilizer synergistic agent has strong penetration effect, and regulates poor fertile soil using organic matter and humus, is rich in nutrients and easily absorbable.    DETAILED DESCRIPTION - Fertilizer synergistic agent comprises 1-2 pts. wt. 5-nitroguaiacol sodium, 8-10 pts. wt. wheat bran, 12-14 pts. wt. rice bran, 6-9 pts. wt. cottonseed hull, 4-7 pts. wt. ammonium nitrate, 40-45 pts. wt. kaolin, 60-80 pts. wt. modified phosphate rock powder, 3-4 pts. wt. attapulgite, and suitable quantity of water, where the modified phosphate rock powder comprises 90-110 pts. wt. rock phosphate powder, 1-2 pts. wt. gamma -polyglutamic acid powder, 4-8 pts. wt. ferrous sulfate, 6-9 pts. wt. calcium bicarbonate, 2-3 pts. wt. Bacillus subtilis, 3-4 pts. wt. silicate inoculant, 18-22 pts. wt. EDTA chelated copper, 24-26 pts. wt. manganese of humic acid, 13-17 pts. wt. black liquor, and 35-45 pts. wt. corn starch. The modified phosphate rock powder is prepared by evaporating black liquor by heating, adding powdered rock phosphate to the hot black liquor, concentrating into solid, calcining the mixture at 400-500 degrees C, grinding gamma -polyglutamic acid powder, EDTA chelated copper, manganese humic acid, corn starch mixture and calcined product, sieving the ground powder through 150 mesh size sieve to obtain mixed powder, adding water, and ferrous sulfate, uniformly mixing, chelating the mixture by heating at 40-60 degrees C for 20 minutes, again adding calcium bicarbonate, stirring, chelating the mixture by heating at 60-70 degrees C for 30 minutes, uniformly stirring, cooling the hot chelated mixture at room temperature, adding B.subtilis and silicate inoculant, allowing the mixture to stand for 7-8 days at below 20-30 degrees C, drying the solid mixture, grinding the dried mixture into fine powder, and sieving the fine powder through 100-120 mesh size sieve to obtain modified phosphate rock. An INDEPENDENT CLAIM is included for method for preparing fertilizer synergistic agent, which involves (a) calcining kaolin at 700-800 degrees C for 3-5 hours, cooling calcined kaolin, grinding cooled kaolin into fine powder, and sieving the fine powder through 100 mesh size sieve, (b) adding wheat bran, rice bran, and cottonseed hull to the fermentation tank, adding suitable quantity of water, fermenting the mixture at 35-45 degrees C for 3-4 weeks, drying the fermented product, and grinding the dried fermented product into fine powder, (c) mixing the fine powder obtained in step (a) and fermented powder obtained in step (b), adding attapulgite, and uniformly stirring to absorb the fermented powder, and (d) adding the remaining materials to the fermented powder obtained in step (c), uniformly mixing, grinding the mixture, sieving the ground mixture through 80-100 mesh size sieve, weighing the sieved powder, and packing the fertilizer synergistic agent.