Aimed at the complex nonlinear dynamic behavior of highspeed hydrostatic gas bearing,a mathematical model of lubrication analysis was established based on the spherical spiral grooved hydrostatic gas bearing.The dynamic pressure distribution and dynamic characteristic coefficients were obtained by solving with the derivative integral method and the finite difference method.The influence of the spiral groove parameters,radial eccentricity,gas supply pressure and speed on the stiffness damping coefficients of gas film under the condition of tangential gas supply was studied.A linear stability calculation model was established to predict the instability speed,and the influence of operating parameters on instability speed was analyzed.The analysis results show that the film damping coefficient is a factor that inhibits gas whirling,and the stability of the film depends on the combined effect of film stiffness and damping.The stiffness and damping of gas film are increased at first and then decreased with the increase of groove width ratio,groove depth ratio and helix angle,and the stiffness is increased with the increase of rotating speed,while the damping is decreased with the increase of rotating speed.The higher the radial eccentricity and gas supply pressure,the greater the film stiffness and damping.By increasing the gas supply pressure and the radial eccentricity in a certain range,the instability speed of the system can be increased.Reasonable selection of bearing structure parameters and operating parameters can optimize the dynamic characteristics of the bearing and ensure the high running stability of the gas bearing.