本文利用傅里叶分析的方法分析高斯光束的衍射特性。高斯光束在与其传播方向垂直的横截面上的复振幅分布具有不可分离变量的e指数函数形式，文章中首先讨论了高斯光束在某一横截面上的复振幅分布的基本特性，基于此推导了高斯光束在传播任意距离后横截面上的复振幅分布，讨论了束腰存在的充要条件，证明了古依位移的存在性，并利用古依位移定义了瑞利散射，讨论了高斯光束经过透镜时的表达形式。

In this paper, the diffraction’s properties of Gaussian beams will be analyzed in Fourier domain. Gaussian beams have a non-separable cross-section amplitude profile. At first the distribution properties of intensity and phase in a given cross-sectional plane of Gaussian beam are discussed. Then the complex amplitude distribution in any cross-section of the Gaussian beam during propagating is derived by using Fourier transform analysis. The condition for a beam to have a waist is found. The existence of the Gouy shift is proved. The effect of lens on Gaussian beam is discussed.