This letter proposes a dielectric helical antenna made of three-dimensional (3-D) printed zirconia ceramic, which possesses a better performance than the conventional metal one. On the one hand, the radiation principle of the proposed antenna is investigated by regarding its structure as a dielectric waveguide. It is found that a dielectric waveguide operating at the cut-off state of higher mode, here is TM mode, can radiate electromagnetic (EM) waves. The propagation constant of EM waves in waveguide is extracted to demonstrate that the dielectric waveguide indeed works as a fast-wave status at this moment. On the other hand, both the far-field and scattering performances between the proposed and conventional helical antennas are comparatively studied. It is observed that the structure composed of dielectric helix and metal ground can achieve similar radiation gain, axial ratio (AR), and AR bandwidth as the conventional all-metal helical antenna, but possessing lower radar cross section at high frequency. Benefited from a ceramic stereolithography apparatus, the proposed structure can be fabricated precisely, and measured results have reasonably validated the simulated ones.