A partial or complete irreversible deformation is generated in the development process of tight deformed reservoirs. Formation permeability and porosity will decrease with various degrees, the resistance to water flooding is large, and it is difficult to form an effective driving pressure system to exploit and develop the crude oil. As the result, the degree of the effective development is low. This paper takes full account of the characteristics of non-linear oil-water two-phase seepage in a low permeability reservoir. Deformed porous media, potential function, pressure function, stream function and velocity function analytical formulations are presented by considering of the influence of stress sensitivity through the superposition principle. According to the material balance theory, the breakthrough time of the dimensionless well pattern unit is derived through the integral of the velocity function. Moreover, according to the constant streamline hypothesis, a motion equation of the isosaturation surface is derived with a characteristic line method. The results show that by this new method, the stress sensitive coefficient has a significant impact on the effective development coefficient. The larger the media deformation factor is, the lower are the effective
development coefficient and the oil recovery.