在被测弱酸或弱碱溶液中加入一定量过量ＮａＯＨ或ＨＣｌ标准溶液，再返滴入ＨＣｌ或ＮａＯＨ标准溶液若干次（如５次），依次测定ｐＨ玻璃电极在被测溶液中的电极电位。根据有关酸碱平衡和物料平衡及非线性回归原理对实验数据进行处理。用牛顿法对非线性回归进行简化计算。以模拟数据研究了选点问题。本方法的突出优点是不需要活度与浓度的换算，不需要另行测定工作曲线。测定了ＮａＡｃ和（ＮＨ＿４）＿２ＳＯ＿４等弱酸弱碱，结果今人满意。 Add a certain amount of excess NaOH or HCl standard solution to the measured weak acid or weak base solution, and then drop several times (eg, 5 times) into standard solution of HCl or NaOH, and then measure the electrode potential of the pH glass electrode in the tested solution. According to the acid-base balance and material balance and non-linear regression of the experimental data processing. Using Newton’s method to simplify the nonlinear regression. The problem of choosing point is studied by using simulation data. The salient advantage of this method is that it does not require the conversion of activity and concentration and does not require separate determination of the working curve. Determination of NaAc and (NH_4) _2SO_4 weak acid weak base, the results satisfactory.