Abstract: The conventional grid method is difficult to describe condensate gas reservoirs with thin oil ring. Based on the bedding grid and horizontal grid, mixed grid-modeling method was established by analyzing oil ring distribution and the existing reservoir simulation grid technique. The bedding grid was used to describe distribution of gas reservoirs, and the horizontal grid was used to describe distribution of oil rings. Both grids were effectively coupled into a mixed grid. In the mixed grid, the bedding grid was pinched out at the gas-oil contact surface and coupled with the horizontal grid in geometric shape. The non-adjacent grid conductivity model was used to calculate the flow transmissibility coefficient of fluid flow from the horizontal grid to the bedding grid. The mixed grid method could avoid limitations of bedding grid for describing distribution of oil ring with zigzag, decline the grid number in description of oil ring and enhance calculating velocity in numerical simulation. The dynamic development performance of thin oil ring and the characteristics of bottom water coning could be effectively simulated by this method, the simulated results are more reasonable.