<p>This study investigates the problem of the transient response of a deep-buried cylindrical lined tunnel in an unsaturated porous medium, subjected to internal explosion, considering the dynamic soil-lining interaction. Based on the mixture theory and continuum mechanics, the two-dimensional governing equations for the liner and surrounding unsaturated soils subjected to internal explosion are derived. The time domain solutions for the liner and surrounding soil are obtained through Durbin’s numerical inversion method. A set of media parameter studies have been conducted to understand the influence of the saturation (<i>S</i>_r), orosity(<i>n</i>), and additional mass density (<i>ρ</i>_a) on dynamic response. The numerical solutions show that as <i>S</i>_r increases, the radial displacement and circumferential stress amplitude at the inner surface of the lining increase by 9% and 8%, while the peak pore pressure at the contact interface with the unsaturated soil decreases by 51%. The amplitude of the radial dynamic response of the unsaturated soil gradually decreases, the pore pressure amplitude decreases by 55%, and the influence range expands by 39%. As <i>n</i> increases from 0.1 to 0.5, the peak dynamic response of the lining inner surface slightly decreases. The peak values of radial stress, circumferential stress, and pore pressure in the soil increase by 229%, 311%, and 20%, respectively, while the scope of influence is reduced by 50%. As <i>ρ</i>_a increases, the radial displacement and the circumferential stress peak at the cavity surface are reduced by 9% and 10%. Concurrently, higher peak dynamic responses within the soil are accompanied by earlier peak occurrences, with a 9% reduction in the affected area. These results provide theoretical support for the internal blast resistance of the tunnel.</p>