provided are a new paenibacillus sp . strain , the deposit number of which is cgmcc no . 8333 , and a method for culturing the exopolysaccharide ; and an exopolysaccharide having a structural formula as shown in formula being produced by the strain , as well as a production method thereof and its use in promoting the propagation of bifidobacterium . the exopolysaccharide shown by formula has a moderate degree of polymerization and has the functions of promoting the propagation of bifidobacterium , as well as adjusting human intestinal microflora .