The invention discloses modified chitosan pakchoi concentrated fertilizer with high infectious microbe inhibiting activity. The modified chitosan pakchoi concentrated fertilizer with high infectious microbe inhibiting activity comprises the following components in parts by weight: chitosan cationic solution, cinnamic acid, cerium oxalate, humulone, algin, shrimp and crab shells, tremolite, iron-containing waste residue, nano carbon, EM microbial agent, zinc methionine complex, ethoxy quinoline, porous high-activity humic acid, superfine glass fibers with micropores, O-carboxymethyl chitosan and right amount of weakly acidic small molecular group activated water. The modified chitosan pakchoi concentrated fertilizer with high infectious microbe inhibiting activity adopts chitosan rare earth cerium copolymer carried by the superfine glass fibers, supplement of cerium oxalate and antibacterial cultivation on the pakchoi are realized, and the weakly acidic small molecular group activated water and O-carboxymethyl chitosan treated cinnamic acid are combined, so that antibacterial, disease-resistant and high-efficiency cultivation is promoted, and natural environment-friendly cultivation is realized; meanwhile, shrimp and crab shell waste, tremolite, sandy soil and iron-containing waste residue are combined for composting, and the fertilizer has good permeability, is rich in nutrients and can promote high-efficiency cultivation of the pokchoi.