The invention relates to a vector used for displaying antigenic 
epitope by using 
hepatitis B 
virus core particles, an animal vaccine, and a preparation method thereof. According to the invention, 
a DNA artificial synthesis method is adopted, and a coding 
DNA sequence of 
amino acid necessary for 
hepatitis B 
virus core protein is synthesized. In the synthesis process, a coding 
DNA sequence of 
hepatitis B 
virus core protein true 
peptide 1-149 site 
amino acid is adopted as a framework; 79-82 site 
amino acid coding sequence in the framework is removed, and only coding 
DNA relevant to virus particle 
assembly is preserved; for facilitating the 
insertion of other antigenic proteins in the 
hepatitis B virus 
core particle protein, a segment of DNA sequence coding flexible 
peptide is specially inserted at a position of the 79-82 site amino acid, and three 
endonuclease sites are introduced into the sequence, such that 
gene operation is facilitated; the above synthesized DNA segment is cloned into a 
gene cloning vector pUC18, such that a special vector pZNVC used for displaying antigenic 
epitope is formed; a synthesized DNA segment of an 
antigenic protein gene or coding 
epitope is inserted into pZNVC, and 
fusion protein is expressed in prokaryotic organisms or eukaryotic organisms. 78 amino acids on N-end of 
hepatitis B virus and 68 amino acids on C-end of 
hepatitis B virus can be folded into two columnar bodies, such that building blocks used for assembling the 
core protein particle are formed; flexible 
peptide forms a bond connecting the two columnar bodies; and proteins inserted between the flexible peptide protrude on the surface of the viral particles. The flexible peptide is composed of a series of small amino acids without 
side chain, and has certain flexibility. The flexible peptide does not affect the 
hepatitis B virus core particle protein and 
antigenic protein in independently and respectively folding into natural molecular structures. pZNVC is used for displaying 
antigenic protein antigenic epitopes, such that the existence state of the antigenic epitopes on natural 
pathogen outer membrane can be simulated to a maximal extent.