The present invention discloses a quadri-filar helix antenna structure, which comprises a cylindrical body made of a dielectric material with a relative dielectric constant εr greater than 4, and four radiating metal plates disposed on a distal end surface of the cylindrical body and extended along the radial direction of the center of the cylindrical body to its periphery and then along the radial direction in a spiral course on the circumferential surface thereof to its periphery on the other end respectively, wherein the ends of every two adjacent radiating metal plates are coupled with each other to constitute two sets of antenna structures, a penetrating hole is disposed at the central position of the cylindrical body and is precisely embedded into a coaxial cable, and a shield cable disposed at the periphery on one end of the coaxial cable is coupled to an end of another set of antenna structure. Therefore, the antenna not only reduces the overall volume, but also greatly lowers its production costs.