Disclosed is a promoter, a vector and an application thereof. The promoter includes a promoter core region sequence that includes at least an upstream 91-180 bp interval sequence of Corynebacterium glutamicum SEQ ID NO: 6 gene coding sequence ATG. The promoter and a gene fragment are constructed to form an expression cassette, which can express a large amount of protein in prokaryotes; in particular, after being induced by an inducer, the protein expression activity is significantly higher than that of conventional Ptac.