Abstract: Based on the theories of coordinate conversion and space transformation, this paper first transforms the geometric parameters of reservoir and completion in anisotropic space into isotropic space. Then it substitutes these parameters after equivalent treatment into the skin model in isotropic. Finally a computation model is developed for calculating the skin of directional wells with perforated completion in anisotropic reservoirs. The effect of formation damage and a crushed zone is considered in the model. The model proved to be right through finite element method, and a practical example was computed also. The model has wide adaptation range and may provide help for completion design and productivity prediction of directional wells.