多点变位计按其原理可分两类：一类将位移传感器安设于钻孔内部，直接测量被测部分；另一类传感器置于孔口，间接测量被测部分．但后者的缺点是增加了位移传递误差．精度测试设备由尾座、约束墙、测头三部分组成，分5方面考察测杆位移传递精度：（1）迟滞（死区）非线性；（2）迟滞；（3）单向线性；（4）小位移特性；（5）重复误差．此外，摩擦、杆件断面尺寸、材料、长度及张力等参量对精度具有一定影响． Multi-point displacement meter according to its principle can be divided into two categories: one kind of displacement sensor installed in the borehole, the measured part of the direct measurement; another type of sensor placed in the orifice, indirect measurement of the measured part. But the disadvantage of the latter is that it increases the displacement transfer error. Accuracy testing equipment consists of the tailstock, restraint wall, the probe consists of three parts, measuring rod displacement transfer accuracy in five aspects: (1) hysteresis (dead zone) nonlinear; (2) hysteresis; (3) unidirectional linear; 4) small displacement characteristics; (5) repeat the error. In addition, friction, rod section size, material, length and tension and other parameters have a certain impact on the accuracy.