回顾了窄线宽激光器线宽测量的各种方法和发展过程，介绍了利用光外差法测量窄线宽激光器线宽的基本原理，描述了双光束外差法和延时自外差法的不同测试机理。针对延时零拍自外差法容易引起的系统误差，说明了光源调制和光路调制移频非零拍自外差法不同改进方案的优缺点。综述了窄线宽激光器测量线宽的新方法。对窄线宽激光器线宽测量方法进行了较全面的梳理，从发展过程看双光束外差法和延时自外差法有着各自的测量优势。

The measurement methods of narrow linewidth lasers are reviewed. The basic principle of narrow linewidth laser measurement based on optical heterodyne method is introduced. The testing mechanisms of double-light-beam heterodyne and delayed self-heterodyne methods are described. For the systematic error frequently introduced in delayed zero frequency self-heterodyne method, source modulation and path modulation non-zero frequency self-heterodyne methods have been developed, and these improved methods have their advantages and disadvantages, respectively. Moreover, the new measurement methods of narrow linewidth lasers are summarized. The full spectrum of measurement methods of narrow linewidth lasers is shown, and it is seen that double-light-beam heterodyne and delayed self-heterodyne methods can find superiority for different conditions.