光电液位传感位移测量系统中，液体作为测量的特殊敏感元件，其准静态特性研究的滞后一直制约着系统进行准静态测量的应用。为此，建立了三通道连通管模型，推导了液位振荡的运动方程。通过分析知连通管的直径、液体总长以及液体的运动粘滞系数是影响液体准静态特性的主要因素。在此基础上进行了准静态特性实验。实验结果验证了液位振荡规律，得到了各系统参数对液位振荡的影响特性,从而得到系统的优化准则。

Liquid is a special sensing unit in opto-electric liquid level sensing measurement system. The lag of its quasi-static characteristic research restricts the system to be used in the dynamic measurement. To resolve this problem, the mathematical model of liquid flows based on a three-channel connected pipe is set up, and the mathematic equations of liquid fluctuation in the three-channel connected pipe are presented. From the analysis of the diameter of pipe, the total length and movement viscosity coefficient of the liquid are the key elements which influence quasi-static characteristics of the liquid. The quasi-static characteristics experiment is finished. The fluctuation law of the liquid level is validated, and the effect characteristic of the system parameter on liquid level fluctuation is obtained. The system optimization criteria is obtained.