The invention provides a tunneling field effect transistor which comprises a substrate with the formation of a fin with an epitaxial, first and second grids formed on opposite side walls of the fin, a first gate dielectric layer which is formed between the first grid and the side wall of the fin and the bottom surface of the first grid, a second gate dielectric layer which is formed between the second grid and the side wall of the fin and the bottom surface of the second grid, and source and drain regions which are formed at one side of the first grid and one side of the second grid. According to the tunneling field effect transistor with the structure, through controlling the width of the fin, a narrow tunneling junction without the limitation of impurity injection diffusion is realized, the tunneling current is increased, and the conduction current is further raised through increasing an effective tunneling area.