Abstract: Metalenses and multi-diffraction-lenses (MDL) play a crucial role in focusing imaging applications. However, metalenses have their own limitations in terms of large aperture and processing, and MDL are unable to achieve truly high transmittance in terms of transmittance. Aiming at the above problems, a single-layer ring band discretized planar lens was designed by replacing each ring band of a MDL with multiple unit structures of a metalens, and the ring band discretisation of a MDL was successfully realised by using Si, a high refractive index material, as the phase modulation unit and the substrate. In addition, the structural properties and optical performances of the ring-band discretized planar lens, metalens and MDL were compared and analyzed. The results of simulation show that the ring-band discretized planar lens not only achieves beam focusing, but also has a high transmittance of 76%, which is 25.3% higher than that of the MDL. The maximum depth-to-width ratio of the structure is 8.9 : 1, which is 50.5% lower than that of the metalens, and it has certain advantages in batch processing. The band discretized planar lens has the advantages of both metalens and MDL, and shows a broad application prospect in optical system integration, infrared imaging, optical sensing, and other important fields.