A numerical simulation method was presented to optimize the design of high stiffness horizontal aerostatic spindle,which was verified through experiments.The standard elliptic partial differential equations were got by converting the common gas lubrication Reynolds Equations with mathematical transformation.By using MATLAB software PDE toolbox as a solver,the calculation of static performance of aerostatic spindle was carried out through programming iterative calculation algorithms.The effect of structure parameters on aerostatic spindle performance was analyzed,and the optimal structure parameters were chosen.The radial and axial stiffness of the optimized aerostatic spindle was tested,the experimental results verified the accuracy of the simulation analysis method.