Abstract: An inflated membrane tube is a kind of flexible structure. Its deformation will result in a change in the inner pressure and then affect the stiffness and deformation of the enveloping membrane. This phenomenon reflects the interaction between the pressure of inner air and the deformation of enveloping membrane. The authors, using the finite element method, analyze the effect of air-membrane interaction on the dynamic properties of an inflated membrane tube and its variation with influencing factors. The inner air is treated as a kind of linear potential fluid to consider the effects of air-membrane interaction and added mass of the inner air. Three finite element models of the inflated membrane tube are developed with different methods to treat the inner air, i.e., the inner air is treated respectively as the static boundary conditions of the enveloping membrane, the static boundary conditions plus the added mass, and a kind of linear potential fluid. The numerical results obtained from these three models are compared to study the influences of air-membrane interaction and added mass on dynamic properties of the tube and their variations with the initial inner pressure, slenderness ratio, membrane thickness and constraint type. The comparisons indicate that air-membrane interaction and added mass of the inner air have little influence on the low-order modal shapes; air-membrane interaction plays a significant role in the natural frequencies while the added mass of inner air has a very small effect; with an increase in the initial inner pressure and slenderness ratio, the influence of air-membrane interaction on natural frequencies varies differently for different orders; The influence of air-membrane interaction on natural frequencies decreases with the increasing membrane thickness and is gradually strengthened when the end constraints are weakened. The present research reveals the dynamic effect of air-membrane interaction and is helpful to the understanding of the dynamic behavior of inflated membrane tubes for their rational and reliable design.