We set up the nonlinear ordinary differential equations(ODES) of the hea-vier pellets for two-phase flow in a horizontal separator.The solutions of theODES are obtained and the movement orbit and velocity of pellets are calculatedusing separating variable and iterative approach method.According to experimentdata we could determine the coefficients of the resistance of the flowing pellets.This paper also discusses convergent problem of the iterative approach solutions.Results analysis and numerical examples are illustrated