The invention provides a circular waveguide antenna based on a dielectric lens, so as to solve the technical problem of insufficient collection of incident waves in the prior art. The circular waveguide antenna based on the dielectric lens comprises a circular waveguide and a dielectric lens fixed with the receiving end, wherein the upper bottom surface of the dielectric lens is located at one side of the receiving end of the circular waveguide; the dielectric lens comprises a cylindrical medium and multiple circular cylindrical medium layers which are nested sequentially from inside to outside with the cylindrical medium as a center, the lower bottom surface is thus a spherical surface, the upper bottom surface is a planer surface, the side surface has a round table body structure with aninward concave arc surface, the cylindrical medium and the circular cylindrical mediums comprise multiple first cylindrical mediums and first circular cylindrical mediums laminated vertically respectively, and the first cylindrical medium and the first circular cylindrical medium are formed by multiple first basic units and second basic units in a joint mode. Material parameters at different positions can be realized through changing the size of spherical space inside the first basic unit and the second basic unit, electromagnetic waves can be effectively converged, and the manufacturing costis low.