A new vertical spindle supporting system was presented to improve the stiffness of an aerostatic bearing and to meet the requirements of machine tools for aerostatic bearings. The Computational Fluid Dynamics (CFD) and Finite Volume Method (FVM) were used for simulating the flow field and pressure field inside the aerostatic bearing and for researching its static characteristics. The grid subdivision in the direction of film thickness was implemented while establishing the grid of the gas film. Finally, a 2 μm/grid on the thrust surfaces and 2.5 μm/grid on the radial surfaces along the film thickness direction were achieved. Results indicate that the gas velocities around the orifices are about 200 m/s and 1 m/s when the pressure distribution of the gas film is changed and the loading capacity is achieved 3 508 N/μm. It concludes that the static characteristics of the aerostatic bearing can be improved by increasing supply pressures or decreasing the diameters of orifices.