The theoretical basis of traditional orifice type aerostatic thrust bearing is based on the premise that the orifice diameter is much larger than the gas film clearance.In order to explore the static performance of aerostatic thrust bearing with microporous restrictor of the same order of magnitude as the gas film clearance,the model of microporous restrictor aerostatic thrust bearing was established,and the threedimensional simulation was carried out by CFD software to study the influence of gas film clearance,aperture and gas supply pressure on the static characteristics of the bearing.The simulation results were compared with that of annular throttling hydrostatic gas thrust bearing.The results show that there is a pressure drop at the orifice outlet for both microporous and annular throttling.The velocity and pressure change of the microporous restrictor at the edge of the orifice outlet is more gently than that of the annular restrictor at the edge of the orifice outlet,and the bearing stiffness is improved.The bearing capacity of the bearing is decreased with the increase of gas film clearance,the bearing stiffness is increased with the decrease of the orifice diameter of the microporous restrictor.Under the same aperture,the larger the air supply pressure,the greater the bearing capacity and stiffness.