Abstract: The non-linear Poisson-Boltzmann equation （PBE） which describes the electrical double layer established when protein is situated eccentrically in the water wool of reversed micelles is solved numerically in bispherical coordinates. The PBE which describes the electrical double layer established when protein and reversed micelles exist separately, protein is situated in the water wool of reversed micelles concentrically, are also solved numerically, the non-linear charge regulation boundary condition has been treated on the inner surface of reversed micelles. Based on the above numerical solution, a calculation is performed for the electrostatic interaction energy related to the eatraction of protein into the water wool of reversed micelles by free energy method. The effects of ion species, concentration in the water wool of reversed micelles and coupling aqueous phase, molecule size and number of charge of protein extracted, eccentric distance on the extraction system have been predicted based on the results of electrostatic interaction energy calculation.