The invention discloses genetically engineered bacteria capable of increasing the yield of lactoyl-N-trisaccharide II and a production method, and belongs to the field of microbial genetic engineering. According to the invention, the expression of glmM, glmU, glmS and lgtA in a lactoyl-N-trisaccharide II synthetic pathway is regulated and controlled in a combined manner, so the carbon flux of a metabolic pathway is accurately regulated and controlled, and the metabolic pressure is relieved; the expression of wecB, nagB and lacZ in an escherichia coli host, namely the lactoyl-N-trisaccharide IIsynthetic pathway is knocked out, so the yield of the lactoyl-N-trisaccharide II is further increased; in a flask shaking experiment, the capacity of escherichia coli for producing the lactoyl-N-trisaccharide II is increased to 4.82 g/L from 0.53 g/L; in a fermentation tank with a volume of 3 L, the yield of the lactoyl-N-trisaccharide II reaches 46.2 g/L; and thus, thegenetically engineered bacteria have industrial application prospect.