Abstract: High-performance servo hydraulic cylinders utilize hydrostatic bearing oil chambers as the core part of guiding sleeve structure. The effects of Wang-shaped and rectangular chamber guiding sleeve structures on the lubrication characteristics of the oil film under constant flow supply conditions were analyzed. The transient finite element method with dynamic mesh technology was employed to investigate the transient lubrication characteristics of two chamber shapes under different inlet flow rates and piston rod velocities. The analysis focused on transient temperature, pressure, and flow fields. The results show that the oil film temperature of Wang-shaped chamber is generally higher than the temperature of rectangular chamber. The Wang-shaped chamber exhibits better radial load-bearing stability. Under the same conditions, the flow velocity at the sealing edge of the Wang-shaped cavity is greater, which is conducive to the renewal of the oil film and heat dissipation, thereby maintaining better load-bearing stability. Under the conditions of eccentric load, the internal pressure gradient of Wang-shaped chamber is obvious, allowing the piston rod to maintain the stable operation under the conditions different eccentric load.