Abstract: The hydrodynamic bearing ability of slipper/swash plate pair in axial piston pumps was studied under steady state. Considering the effect of centrifugal on the slipper tilt and analyzing the other forces on the slipper, a tribo-dynamic model of slipper/swash plate pair under steady condition was developed to study the law of hydrodynamic lubrication of oil film between the interfaces. The result shows that the gap between friction pair is always convergent wedged-shape and the tilting azimuth angle of slipper is around 170 degrees basically. This micro motion of slipper is helpful for the hydrodynamic lubrication film. The simulation result was testified well by the experiment.