The invention belongs to the technical field of genetic engineering, and particularly relates to a genetically engineered bacterium for producing N-acetylneuraminic acid through xylose induction. Escherichia coli is used as a starting strain, an N-acetylglucosamine synthesis pathway is integrated on a genome, an N-acetylglucosamine 2-epimerase gene bAGE and an N-acetylneuraminic acid synthetase gene neuB from collar algae are introduced, an N-acetylneuraminic acid synthesis pathway is constructed, and a key gene nano ATEK of a catabolism pathway of the N-acetylneuraminic acid is knocked out. Meanwhile, metabolic pathways of precursor substances required by synthesis of the N-acetylneuraminic acid are subjected to multi-copy reinforcement, part of bypass metabolic pathways are knocked out, key enzyme genes for producing GlcNAc and Neu5Ac are optimized according to different copy numbers, the optimal proportion of the key enzyme genes is finally determined, and the high-yield strain of the N-acetylneuraminic acid is obtained. The highest yield of the N-acetylneuraminic acid can reach 28g / L, the highest production intensity can reach 0.67 g / (L*h) which is the highest value reported at present, and the N-acetylneuraminic acid has important industrial application value.