Abstract: Study of method in core analysis by MRI and Image processing technology.Principle of NMR imaging and Image processing function are described.Through the study of testing rock and math method,and established the methods to analysis formation structure,porosity and porosity distribution image,permeability and permeability distribution image,movable fluid percentage image,identification of water and oil image.The results indicated that testing rock by using MRI technology not only determine porosity and permeability parameter,but observe porosity and permeability distribution image also.Movable fluid in rock is observed by movable fluid percentage image.The method of identification of water and oil give distribution of water and oil in rock,oil and water saturation is calculated.Method in core analysis by MRI can apply to reservoir evaluation,development, experiment,enhance recovery ratio research in oil field.