本文提出了具有相同电荷的同号离子间作用力相等的假定,简化了Pitzer的电解质溶液活度系数计算公式,用此公式,计算了H_2SO_4-CoSO_4-CuSO_4水相体系各单个离子活度系数以及水的渗透系数。本文还应用由作者提出的工作参考态法,应用改进的Scatchard-Hildebrand模型计算了EHEHPA-CoSO_4-CuSO_4萃取体系中有机相各组分的活度系数以及萃取反应热力学平衡常数。 In this paper, the assumption of equality of ions of the same number with the same charge is proposed, which simplifies the calculation formula of Pitzer electrolyte solution activity coefficient. Using this formula, the individual ion activity coefficients of H_2SO_4-CoSO_4-CuSO_4 aqueous system and Water permeability coefficient. In this paper, we also apply the working reference method proposed by the authors. The activity coefficients of the organic components in the EHEHPA-CoSO_4-CuSO_4 extraction system and the thermodynamic equilibrium constants of the extraction reaction were calculated by the improved Scatchard-Hildebrand model.