The invention relates to a genetically engineered bacterium for high producing beta-alanine, co-culture preparation of D-pantothenic acid, a construction method of the genetically engineered bacterium and application of the genetically engineered bacterium to co-culture preparation of the D-pantothenic acid. According to the invention, original promoters of panD, aspC and ppc genes on a genome are replaced with a pTrc99A-derived Trc promoter and a ribosomebinding site (RBS) sequence so as to enhance synthesis of the beta-alanine, and genes pykA and pykF are knocked out to block consumption of phosphoenolpyruvate (PEP) and modify a glucose uptake path of escherichia coli, and thus, a non-phosphotransferase system (non-PTS) transport system is enhanced to block a PTS transport system, and synthesized precursor PEP is accumulated; on the basis, heterologous aspartate decarboxylase genes panD and aspC of E.coli W3110 are introduced to enhance the enzyme activity of key enzymes, so that supply and conversion of beta-alanine precursors are enhanced; gdhA genes of E.coli W3110 are introduced to enhance cyclic regeneration of coenzymes NADP / DNAPH, and finally, the titer of the beta-alanine is increased from 0 to 2.48g / L. The strain and a previous D-pantothenic acid producing strain DPA 21 / pBCST3 undergo construction of a primary co-culture system; the inoculation ratio is optimized; and when the inoculation ratio of the two strains is 1: 1, the co-culture strain can produce 3.08 g / L of D-pantothenic acid in a same fermentation medium.