提出了一种利用激光自混合干涉效应的差动式位移测量系统， 建立了系统的数学模型，经仿真分析及实验验证表明： 和单激光管结构相比， 该系统位移分辨力提高了二倍， 达 １／４ 光波波长， 且能大大减小光反馈强度引起的噪声及温度干扰。 A differential displacement measurement system using laser self-mixing interference effect is proposed. The mathematical model of the system is established. The simulation analysis and experimental verification show that the displacement resolution of the system is doubled compared with single laser tube , Up to 1/4 wavelength, and can greatly reduce the noise caused by optical feedback and temperature interference.