This article introduced the basic theory and method of measuring the velocity of light using the method of phase difference and how to measure the velocity of light using phase difference in air.

• 摘要介绍了一台自制的利用相位差法测量光速的仪器的基本原理和方法，并通过对光在空气中的传播速度的测定，使大家对用相位变化测量光速仪器有所了解。