Abstract: In order to deeply explore the bearing performance and law of aerostatic bearing under radial and axial combined working conditions, a T-type composite structure aerostatic bearing platform had been designed and developed. Combined with the 3D model of the T-type composite structure aerostatic bearing platform, the fluid lubrication theory and the finite volume method had been used to numerically calculate the aerostatic combined bearing and the single radial bearing. The effects of eccentricity, air supply pressure and rotational speed on the bearing capacity and stiffness of the aerostatic bearing had been explored. The results show that the bearing capacity of aerostatic bearing has gradually increased with the increase of eccentricity and air supply pressure. The bearing performance of a single radial bearing was better than that of a combined bearing.