A dielectric lens, where the dielectric lens is a cylindrical lens or an ellipsoidal lens whose cross-sectional profile is a quasi-ellipse, and the dielectric lens is formed by piling a plurality of units. Dielectric constant distribution of the units in the dielectric lens enables a non-plane wave in a minor axis direction of the quasi-ellipse to be converted into a plane wave through the dielectric lens. The units of the dielectric lens are prepared through extrusion, injection, molding, computer numerical control (CNC) machining, or a three dimensional (3D) printing process technology, and the units may be assembled through gluing, welding, structural clamping, or a coupling printed through 3D printing. When the dielectric lens is applied to a multi-beam antenna, a system capacity of a communications system can be increased. In addition, a thickness of the lens is reduced using the multi-beam antenna.