Hollow optic fiber delivery of CO₂ and other mid-infrared lasers 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 tubes 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 （150/-196 ℃）， the transmission loss remained stable， showing its value for practical applications.