征，并精确测定出基本电荷量值，成为物理学史上的一个经典实验，其对近现代物理学的发展具有重要的意义. 密立根油滴实

验数据的精度取决于油滴的选取，而实验教材只指出如何选择油滴，却未说明背后的物理原因. 本文将该实验中的油滴作为

研究对象，从实验的理论分析方面着手，进行细致的分析与解析推导，并结合实验误差分析，挖掘出油滴选取的物理内涵，为

油滴的合理选取提供理论支持.

of physics，to reveal that magnitude of any charged bodies takes separation value，and determine magnitude of

the electron’s change. Suitable choices for oil-drop will help us to improve the measuring accuracy. Some books about

physical experiment provided choice rules，however it is not explained the reasons why we shall make that

choices. In this paper，we focus on choice rules for the oil-drop experiment，and reveal the physical reasons by

combining theoretical and error analysis. These results presented in this paper will provide theoretical support for

choice rules of oil-drop.