The invention belongs to the technical field of bioengineering, and discloses a gene-engineering bacterium, a construction method of same, and a method of producing vanillin. In the gene-engineering bacterium, the metabolic pathway of 3-dehydro-shikimic acid is modified, wherein a shikimic acid dehydrogenase encoding gene is deleted and a vanillin degradation related gene is also deleted, so that the bacterial strain can accumulate a large amount of 3-dehydro-shikimic acid; in addition, expression on a 3-dehydro-shikimic acid dehydratase gene, an O-transmethylase gene and a vanillic acid reductase gene and two genes in the metabolic pathway of the 3-dehydro-shikimic acid are enhanced, so that yield of the vanillin is increased, degradation of the vanillin is reduced and quantity of the vanillin in a fermentation liquid is increased, thus improving the capability of fermenting production of the vanillin by the bacterial strain. A test proves that the gene-engineering bacterium uses glucose or glycerol as a substrate for producing the vanillin, wherein the yield of the vanillin is increased significantly. A vanillin fermentation liquid produced with the method is free of an isovanillin impurity, so that subsequent separation is easy to carry out.