Abstract: Pendulum wire is important in dam horizontal displacement monitoring.This paper discussed its attribute issues.It was pointed out that the dam deflection was in fact the dam horizontal displacement． Further, the necessity to correct the deformation monitoring precision in the criterion SDJ336－89 was stated here. The point view that section inclined deformation was not dam inclined deformation was advanced and monitoring by pendulum wire could provide conditions for single－parameter multi point numerical model analysis．

摘要： 垂线监测是一种监测大坝水平位移的重要方法，就其属性问题进行讨论，指出挠度其实就是水平位移，分析了对SDJ336－89 规范中变形监测精度进行修正的必要性，提出坝体截面倾斜变位不等于坝体倾斜变位，指出垂线监测为单参数多测点数模分析提供了条件。