The utility model discloses a field local enhancement device with a semi-elliptical groove constructed on the surface. The field local enhancement device comprises a three-layer structure, wherein thethree-layer structure comprises a first-layer structure, a second-layer structure and a third-layer structure, the first-layer structure, the second-layer structure and the third-layer structure forma coaxial conical structure layer by layer from inside to outside, and the third-layer structure can be divided into an upper half part with a semi-oval groove constructed in the surface and a lowerhalf part with a smooth surface. According to the technical scheme, the hybrid plasmon effect is adopted, light can be limited in the low-refractive-index dielectric layer for propagation, and the propagation loss of the light can be reduced. According to the technical scheme, stronger nanometer focusing can be realized, when a radially polarized cylindrical vector light beam is vertically incident to the structure, more light energy is coupled by using the structure of the concave lens, and super-strong focusing is realized at the tip.