The invention discloses a polypeptide. The amino acid sequence of the polypeptide is as shown in SEQ ID No. 1 or SEQ ID No. 2. The invention further provides a pharmaceutical composition, foods or health care products containing the polypeptide, and corresponding application of the polypeptide. An epitope peptide is obtained through screening, the epitope peptide is identified through in-vitro ELISPOT, cell killing experiments and the like, a theoretical basis is provided for subsequent development of tuberculosis vaccines and diagnostic preparations based on drug-resistant mutation antigens,and more options are provided for design of tuberculosis multi-epitope vaccines based on mixed T cell epitopes.