Using the technique of expanding the window funetion of hard-edge apertures into the superpositionof complex Gaussian funetions , the analytical expressions of the intensity distribution of Gaussian beams passingthrough an ABCD optical system with one-dimensional double-slit hard-edge apertures and Gaussian beamspassing through an ABCD oplieal system with two-dimensional double-slit hand-edge apertures are derived fromCollins diflraetion integral, The propagation distanee B, the aperture width d, and the waist size W of theGaussian beam are adjusted.Then ,the MATlAB software is used to generate the intensity distribution imagesunder different eonditions,The transmission and transformation rules of the Gaussian beam through a double-slithard-edge aperture are analyzed and compared.