To analyze the effect of a variable section throttle on the performance of aerostatic bearings, an aerostatic bearing model with a variable section throttle was proposed. Furthermore, the dynamic change in the shape of the throttle cavity cross section was realized by deformation of the elastic plate of the bearing surface. First, the coupled partial differential equations of solid plate deformation and gas lubrication were established. Then, they were discretized and solved by the high- precision finite difference and over relaxation iteration methods. The results reveal that the shape of the throttle determines the value of the nozzle coefficient in the numerical calculation. Furthermore, the stiffness of aerostatic bearings with a variable section throttle is 15% higher than that of aerostatic bearings with a rigid throttle, indicating that a variable section throttle allows aerostatic bearings to achieve a greater stiffness under high bearing capacity. The results of the theoretical analysis are in good agreement with experimental results. Moreover, they indicate that a variable section throttle can effectively improve the static characteristics of aerostatic bearings.