The invention provides a recombinant engineering bacterium for efficiently expressing a liraglutide precursor and an application of the recombinant engineering bacterium. According to the invention, asignal peptide and an enterokinase restriction enzyme cutting site are designed at the N end of a liraglutide precursor molecule Arg34G LP-1 (7-37), the C end is connected with termination codon, a target gene is formed, then, the target gene is inserted between two restriction enzyme cutting sites of an expression vector; the recombinant engineering bacterium for expressing the liraglutide precursor is constructed, the engineering bacterium is subjected to high-density fermentation culture and is expressed in the form of an inclusion body of a fusion protein, the expression quantity of the recombinant fusion protein is high, the recombinant fusion protein accounts for about 25%-35% of the total protein of the bacterium, and the expression quantity of the inclusion body of a target protein reaches 15-20g/L. The inclusion body is low in impurity protein content, beneficial to separation and purification, and high in purification efficiency and good in stability, the production cost isgreatly reduced, the production efficiency is improved, and the inclusion body has the good application prospect in the field of diabetes treatment medicine preparation.