Hollow optic fiber delivery of CO2 and other mid-infrared lasers still faces several challenges in terms of transmission loss, bending flexibility and reliability, which limits its applications in laser medicine, flexible industrial processing, and intelligent sensing. A flexible, low-loss mid-infrared hollow fiber with enhanced PI/Ag/AgI interfacial bonding strength has been developed by utilizing plasma activation of polyimide (PI) structural tubing and a dynamic liquid-phase deposition process. The results showed that after plasma treatment, the N-C bonds on the surface of PI were converted to N-O bonds and active groups such as carboxyl were formed. This results in enhancement of surface hydrophilicity and the interfacial bonding strength between PI and Ag/AgI layers (from level 0 to level 2) without noticeably increasing surface roughness. The as-fabricated PI hollow fiber (ID=2 mm) exhibited a low-loss transmission window within 8~15 μm wavelength range, achieving a linear transmission loss as low as 0.05 dB/m at 10.6 μm. When bent 180° with a radius of 20 cm, the loss increased only to 0.55 dB/m. The fiber could deliver a 30 W CO2 laser beam for 300 s at 150°C without damage. After 400 min of vibration testing and 120 min of high-low temperature aging (-196°C/150°C), the transmission loss remained stable, showing its value for practical applications.