Abstract: A dielectric structured lens formed by varying the high-refractive-index square dielectric holes was proposed. This lens can realize higher energy efficiency compared with the high-refractive-index square dielectric metal structured lens. The energy efficiency has achieved 44% by finite difference and time domain(FDTD) algorithm, and the spot size leads to the diffraction limit. Second, the dispersion characteristic of the lens was researched, it has the counter dispersion characteristic with the geometrical optics lens, so lens group make up of those dielectric structured lens and the geometrical optics lens can be used to clear dispersion. In addition, it overcomes the limitation of feature size of the large numerical aperture(NA) lens, so the large NA lens can be achieved. Four lens with the same aperture but different focus length were designed for the wavelength 10.6m. The smallest F number has reached 0.25.