The invention belongs to the field of biological medicines and discloses a specific antigen polypeptide for an effector T cell of a hepatitis B virus of a non-human primate cynomolgus monkey, application of the specific antigen polypeptide in diagnostic kits and a vaccine. By analyzing a topological structure of a functional protein structure of the hepatitis B virus, the specific polypeptide for the effector T cell of the hepatitis B virus of the non-human primate cynomolgus monkey is obtained, and by carrying out structural analysis after the rearrangement of relevant polypeptide combinations, a brand-new peptide fragment which can be used for diagnosing the hepatitis B of the non-human primates is screened. In an ELISpot experiment, the obtained peptide fragment is utilized for stimulating the effector T cell in non-human primate diseases infected by the hepatitis B to secrete gamma-IFN, so that the feasibility and treatment value of the peptide fragment in the diagnosis of the diseases are proved. The method is strong in specificity, high in sensitivity and simple and convenient in operation, a diagnostic kit can be developed for the diagnosis and differential diagnosis of the hepatitis B v of the primates in clinical detection, and the foundation is laid for the screening and treatment of zoonoses.