Abstract: Based on the mass conserving boundary condition, a numerical model for cavitation of radial grooved face seals was developed. To achieve the objectives the steady, incompressible, polar coordinate Reynolds equation, including centrifugal effects and the cavitation, was discretized using the control volume finite method and solved numerically by Gauss-Siedel relaxation iterative. The block-weight approach was implemented to deal with non-coincidence of mesh and radial groove pattern in numerical method. The model was used to investigate the effects of working condition and structural parameters on cavitation area. The results indicate that rupture of oil film located where the thickness increased, and the seal dam could prevent cavitation. Cavitated area increased with the increment of rotary speed, by contraries, cavitated area decreased with the increment of groove depth. Cavitated area was dependent on hydrostatic and hydrodynamic effects in radial and circumferential direction.