Abstract: The effects of slip flow on the steady mechanicalperformances of the micro gas bearing are discussed. Considering thedimensional characters of the micro bearing and judging from the flow'sKnudsen number, the flow in the bearing is in the slip regime instead of thecontinuous regime. The modified Reynold's equations of first-order slip-flowand second-order slip-flow for the micro gas bearing are obtained. Solving theReynold's equations for the continuous regime and the two slip regimes with thefinite difference method (FDM), the gas pressure distributions, the non-dimensional load capacities and attitude angles are obtained.The comparisons of the load capacities and attitude angles between the threeregimes are made, and it is shown that the mechanical performance withthe slipregime distinctly differs with that of the continuous regime. Ananalysis illustrates that the slip flow regime has great effects on thesteady mechanical performances of the micro bearing. The second-orderslip-flow model can produce a good result for high eccentricity ratio operation.