摘要： 在大坝变形观测方面，本文对国内外几种观测精度的提法作了分析，并论述了制定“必要观测精度”的思路和方法。另外，还证明了观测误差对间隔位移和累积位移位的影响，其大小是一样的。

Abstract: In this paper, the author makes an analysis to propose several accuracy from internal and external on observation longe dam deformation, and have introduced the thinking and way in making essential observation accuracy. Other, it has proved the function and size are similar to interval displacement and accumulative displacement.