The invention relates to a polysaccharide conjugate vaccine, which comprises a chemical conjugate consisting of a bacterial polysaccharide and a vector protein, wherein the vector protein is a bacterial slime invasion-associated protein, such as a bacillus coli heat-labile toxin B subunit, a campylobacter jejuni flagellum secretion protein A1, a campylobacter jejuni flagellum secretion protein A2, a pneumococcus surface protein and a pneumococcus surface adhesin. The invention further relates to a preparation method for the polysaccharide conjugate vaccine. According to the invention, the mucosa delivery of the polysaccharide conjugate vaccine can be realized on the premise of not adding any other extrinsic protein; and due to the adoption of an immune route, the vaccine is more efficient, convenient and safe to use.