In order to study the bearing characteristics of spiral groove dynamic pressure radial bearing,a three-dimensional physical model was established by using SolidWorks software.Based on the Navier-Stokes equation,the compressible unsteady Reynolds equation was derived.The basic Navier-Stokes equation of gas lubrication was solved directly by CFD technology and fluid dynamics Fluent software,the pressure distribution of the bearing under different rotating speeds and the variation law of the bearing capacity with the structural parameters and operating parameters of the spiral groove dynamic pressure radial bearing were obtained.The results show that the gas film thickness of spiral groove gas hydrodynamic bearing is the smallest in the eccentric direction,and the pressure is larger than that in other areas.With the increase of rotating speed,the maximum pressure gradually increases due to the significant dynamic pressure effect of the bearing.With the increase of structural parameters such as groove length,groove depth ratio,groove number,as well as the increase of operating parameters such as eccentricity and speed,the bearing capacity increases.The bearing capacity decreases with the increase of radius gap.The research results provide a theoretical basis for the design and optimization of spiral groove hydrodynamic radial gas bearing.