A new method to analyze radial characteristics was proposed based on ANSYS Workbench. The finite element model was established based on similar principles of computational fluid dynamics, the pressure field of aerostatic bearing in tiny gas gap was calculated by using the FLUENT module. The strength check was processed by Static Structure analysis module, the capacity of aerostatic bearing was also achieved. Radial stiffness of aerostatic bearing was calculated based on the experimental design of DOE, the effect of the number of circumferential orifice and orifice diameter on the radial stiffness was analyzed. The results show that the stiffness is increased with the decrease of the diameter of orifice and the increase of the number of orifice. The calculation results of the new method have good agreement with the experimental results.