以Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程为基础，通过假设液－液界面的滑动速度比，导出了液－液分层层流流动速度分布的数学模型及液层厚度的计算公式．通过作用于液滴上力的平衡条件来建立液滴的运动方程，分别导出了液滴在连续相及相界面上相对于液体的运动模型．用微粒、微滴联合示踪的激光照相法，实测了液－液界面的滑动速度比．本文模型为进一步研究液－液分离过程提供了基础． Based on the Navier-Stokes equation, the mathematical model of flow velocity distribution in liquid-liquid laminar flow and the formula of liquid layer thickness are derived by assuming the sliding velocity ratio of the liquid-liquid interface. The equations of motion of the droplet are established by the equilibrium condition of the force acting on the droplet, and the movement model of the droplet at the continuous phase and the phase interface with respect to the liquid is derived respectively. The sliding velocity ratio of the liquid-liquid interface was measured by the laser photogrammetry combined with microparticle and droplet tracing. The model provided the basis for further study of liquid-liquid separation process.