液体传动的基础是帕斯卡原理。狭义的液压传动技术指以矿物油作为工作介质，利用液压泵将原动机的机械能转换为液体的压力能，经过各种控制阀和管路来传递与控制液体压力能，借助缸或马达等液压执行元件转换为机械能来驱动工作机构，实现直线往复运动或回转运动。具有功率大、速度低、平稳等优点，在工业生产特别是在机械驱动中被广泛应用。但矿物型液压油存在容易泄漏导致环境污染的问题，同时，矿物油在一定环境下会燃烧。
The foundation of the liquid transmission is the Pascal principle. Hydraulic transmission technology in narrow sense refers to the mineral oil as a working medium, the motive of the mechanical energy into fluid pressure energy use through a variety of hydraulic pump, control valve and the pipeline to transfer and control of fluid pressure, the cylinder or motor and other hydraulic actuators is converted to mechanical energy to drive the working mechanism, realize the linear reciprocating motion or rotary motion. It has many advantages, such as high power, low speed, smooth and so on. It is widely used in industrial production, especially in mechanical drive. However, there is a problem of environmental pollution caused by the leakage of mineral hydraulic oil easily. At the same time, the mineral oil will burn in a certain environment.