Abstract: The gasdynamic bearing with spiral grooves is a type of bearings which play an important role in development of machinebuilding industry. By using the conformal mapping method for curved surfaces, the lubricated spherical surface with a spiral groove pattern is transformed into the lubricated plane with a parallel straight groove pattern, and the equation describing the gas film lubrication between two spherical surfaces is reduced to the Reynolds equation controlling the lubricating film behaviour between two plane strips. By applying Whipple's theory on the recurrent pattern of parallel grooves, some formulae for the axial and radial load-carrying capacity or the gas-film stiffness of the spherical spiral groove bearings are derived and the optimums of the angle of the groove, the ratio between groove width and ridge width, the ratio between the film height above the bottom of groove and the height above the ridge and the relative width of the groove pattern are given. The formulae given in this paper are applicable for the hydrodynamic bearing with small compressibility number and small eccentricity,