对高斯光束在硬边孔径限制下的衍射进行了详细的理论研究，就不同口径的圆孔限制下高斯光束在菲涅耳衍射区和夫琅禾费衍射区的分布进行了理论分析，从而得到了孔径受限高斯光束的横向以及轴向的衍射公式，进而对高斯光束在不同衍射区域内衍射光场分布形状随孔径尺寸变化时的演化规律进行了数值计算，并对小口径光阑受限的高斯光束的衍射与平行光经同尺寸光阑的衍射进行了比较。结果表明在较小口径下，两者的分布基本一致。得到的孔径光阑限制下高斯光束的传输规律为高斯光束在自由空间光通信和光学超分辨中的应用提供了理论基础。

Theoretically, the diffraction of Gaussian beam limited by the hard-edged aperture is studied and the diffraction distributions of Gaussian beam limited by the apertures with different calibers in Fresnel and Fraunhofer zones are analyzed in detail, and the evolution relationship of the diffraction of Gaussian beam and the different size of the aperture in the different diffraction regions is obtained. The results show that the diffraction of Gaussian beam limited by the pupil function agrees with the Rayleigh diffraction when the caliber of the hard-edged aperture is small enough. These propagation rules of Gaussian beam limited by the aperture could promote the applications of Gaussian beam in the optical communication and the optical super-resolution.