A hollow anti-resonant fiber with nested and double cladding structure is proposed. By optimizing the structural parameters, the confinement loss reaches 4 × 10 ^{− 4} dB / km at 1.55 μm, and the ratio of high-order mode loss to fundamental mode loss also reaches 20,000. In the O + E + S + C + L + U band, the loss is <0.01 dB / km and the ratio of high-order mode loss to fundamental mode loss is >10³, indicating that the designed fiber has excellent single-mode characteristics and wide bandwidth. In addition, the manufacturing tolerance of the fiber is also discussed. It is found that the loss can still be maintained below 0.01 dB / km within the tolerance range of 8%. Therefore, we believe that the fiber has potential applications in near-infrared communication and data transmission.