Abstract: In the traditional static pressure air bearing model, the orifice is simplified to a single point, and for double-pad aerostatic bearings, the coupling effect of the upper and lower thrust bearings is ignored. In order to solve this problem, a modified Reynolds equation with pressure equalizing chamber is established. On the basis of considering the coupling effect of double-pad aerostatic bearings, the influence of film thickness, gas supply pressure and equalizing chamber depth on static and dynamic characteristics of double-pad aerostatic bearings is calculated by using finite element method and perturbation method. The results show that the coupling effect of the upper and lower bearings has a significant effect on the performance of the double-pad aerostatic bearings, and the bearing stiffness can be improved by optimizing the depth of the pressure equalizing cavity while avoiding air hammer self-excitation.