Abstract: A linear graphic method for the determination of the equivalence points of weakly alkaline drugs is presented. The titration is carried out potentiometrically. Equal volumes of the titrant are added stepwise. The detection of end point of titration by means of linear graphic method and calculation method is recommended. Weakly alkaline drugs (amobarbital sodium, phenobarbital sodium, aminopyrine, sodium benzoate) have been determined. This method is simple and convenient to operate. The accuracy and precision meet the requirements.