Abstract: Based on the double - resistance model and mass flux criterion proposed in part (Ⅰ) of this paper and by considering the phase equilibria between any one micro -phase and disorder space, the radial distribution function was expressed analytically in terms of local capture probability and local potential energy. The methods for calculating local capture probability and local potential energy were given. Because of the analyticity of the equations for calculating radial distribution function, much less computation time was needed than integral equation methods or molecular simulations. The results were in good agreement with those from molecular simulations. Better results were obtained than integral equations near the first peak.