Abstract: An approximate strength calculation method of eccentrically compressed reinforced concrete members with reinforcement in four faces is given in the design of reinforced concrete structure. But for members with small eccentricity, a cubic equation of the relative neutral axis depth ξ should be solved in the reinforcement calculation, which is rather complicated. All the calculation conditions are systematically discussed and a convenient strength calculation method is deduced in this paper. The relative neutral axis depth ξ of the members with small eccentricity is solved using the approximation method by reducing power in separated regions.