In order to achieve low-loss and bending-resistant mid-infrared laser transmission, the ultra-low-loss hollow-core nested anti-resonant nodeless fiber is studied in the 3 μm band, and the structural parameters of the hollow-core fiber (tube thickness, outer diameter of cladding capillary, core diameter, and nested tube outer diameter) are used for numerical simulation, and the optical fiber transmission loss as low as 0.52 dB/km is achieved in the 3 μm band. By comparing the bending loss and leakage loss of the hollow core anti-resonant fiber and the hollow core nested anti-resonant nodeless fiber, it is prove that the node-less hollow core anti-resonance fiber has lower transmission loss (loss ratio up to 22.87 dB) and better bending resistance (the loss is less than 0.1 dB/m when the bending radius is 6.5 cm) than the hollow core anti-resonance fiber.