The present invention relates to a recombinant fusion protein and a polysaccharide conjugate vaccine. More specifically, the present invention relates to a fusion protein including a pentamer substrate protein and a peptide sequence capable of forming a trimer, an immunogenic composition including the fusion protein, the application of the fusion protein in immunology, a polynucleotide sequence encoding the fusion protein, an expression vector containing the polynucleotide sequence, and a host cell containing the expression vector.