In order to study the steady-state bearing performance of air bearing under static and dynamic pressure,a model of air bearing under static and dynamic pressure was established by using a three-dimensional modeling tool.Based on the continuum equation,the compressible fluid lubrication equation and the gas state equation,the steady-state gas lubrication Reynolds equation under isothermal condition was obtained,and the steady-state bearing capacity of the bearing was calculated.The three-dimensional model for the structure of gas bearing with helical groove orifices was established,the whole fluid field was simulated by Fluent,and the influence of different parameters,such as spiral angle,eccentricity,slot width ratio,slot depth ratio and slot length ratio,on the bearing performance of gas bearings was analyzed.The results show that when the air supply pressure is constant,the bearing capacity of the gas film shows a nonlinear upward trend with the increase of eccentricity,and a downward trend with the increase of slot width ratio.The larger the slot width ratio,the more obvious the downward trend of the bearing capacity.With the increase of groove depth ratio and groove length ratio,the gas film bearing capacity shows a trend of first increasing and then decreasing.The better bearing performance is achieved after the optimization of the bearing structure.