This article studies the static load capacity, dynamic stiffness, and damping coefficient of the externally pressurized annular porous gas thrust bearings. The Reynolds equation for the bearing is established using linear perturbation; for the first time, three degrees of freedom are considered in the modeling. The steady state equations are solved to obtain the static load capacity, and the first-order perturbation equations are solved for the dynamic characteristics. The influences of various bearing parameters on the static and dynamic characteristics are evaluated. Results from the numerical simulation prove that the proposed method is a valid mean of estimating the static and dynamic characteristics of the porous gas thrust bearings.