Center inlet gas bearings with tapered chamber have higher capacity,but big gas cavity and poor stability.The gas bearings with center inlet tapered chamber were improved,and a gas bearing with the annular inlet tapered chamber was proposed.The complete gas field consisting of supply hole and clearance was built up,and a laminar flow model was applied to calculate the pressure distribution,capacity and volume ratio in different structural parameters.The bearing capacity and stiffness of the optimized bearing structure was calculated.The results show that the load capacity and the gas volume ratio of gas bearings are increased with the increase of the height and radius of tapered recess in a certain range.The improved gas bearing has a high load capacity and stiffness,its gas cavity is decreased greatly,and its stability is increased.