Taking the aerostatic journal bearing of pneumatic turbine support structure as the research object,the differential model of the aerostatic journal bearing was established.The bearing capacity,stiffness and gas mass flow were calculated by engineering numerical method.The effect of the throttle parameters on the bearing performance and the comprehensive performances of the bearing under different optimization directions were studied by orthogonal test method.The results show that the sensitivities of the throttle parameters in different optimization directions are different.It is obviously not in line with the design requirements by taking the gas mass flow as the optimization direction,while the bearing has the best comprehensive performance by taking the bearing capacity as the optimization direction.The average gas film thickness,the diameter and number of orifices are the main factors affecting the bearing performance.The smaller the orifice diameter is,the better the bearing performance is.