Provided are an isolated T-cell receptor, a cell modified by same, coding nucleic acids, an expression vector, a preparation method, a pharmaceutical composition, and applications. The isolated T-cell receptor (TCR) comprises at least one of an α chain and a β chain, both the α chain and the β chain comprising a variable region and a constant region, and is characterized in that the T cell receptor specifically identifies antigen Her2/neu expressed by tumor cells, the amino acid sequence of the variable region of the α chain has a consistency of at least 98% with the amino acid sequence as represented by SEQ ID NO : 19, and the amino acid sequence of the variable region of the β chain has a consistency of at least 98% with the amino acid sequence as represented by SEQ ID NO : 20. The TCR specifically identifies the tumor antigen and, at the same time, prevents any possible off-target toxicity reaction. The use of the TCR in modifying an immune cell provides significant antitumor effects.