pH既是电化学中一个重要的基本概念,又是应用得十分广泛的一个溶液化学指标。由于其定义中包含单个离子活度,因而是一个不能直接测量的物理量。pH和液体接界电位如同一对双胞胎,常一起在公式内出现而不能单独测量。由于pH既重要又不能直接测量,从而形成了pH标准独特的实用定义和争论不休的发展历史。本文简要评述了pH标准的发展历史及现行的一些标准,叙述确定这些标准的实验方法,介绍美国国家标准局(现已改名美国国家标准与技术研究院)对pH标准的管理与研 pH is not only an important basic concept in electrochemistry, but also a widely used solution chemistry indicator. Due to the single ion activity contained in its definition, it is a physical quantity that can not be directly measured. pH and liquid junction potential as a twin, often appear together in the formula and can not be measured separately. Since pH is both important and not directly measurable, a unique, practical definition of the pH standard and a history of controversy arose. This paper briefly reviews the history of the development of pH standards and some of the current standards. It describes the experimental methods for determining these standards, and introduces the management and research on pH standards by the National Institute of Standards and Technology (now renamed by the National Institute of Standards and Technology)