Abstract: The model described here is a dual porosity/dual permeabilty core with the superpose grid structure.It can be applied in a rather wide range as compared with the conventional dual porosity/single permeability model.In addition,it has several good feature as compared to both black oil model and mufti-compositional model,for example,a more simplified method to calculate phase equilibrium and the ability to simulate condensate reservoir etc.This papergive maths models procedure of discretization and the approach to get the solution of the maths model.The application of this model in the study of Su 1.condensate reservoir is presented at the end of the paper.