According to the extended Huygens-Fresnel principle and Collins formula, based on complex Gaussian function expansion method, the cross-spectral density formula of elliptically polarized Gaussian Schell-model beam passing through the rectangular aperture was derived. Meanwhile combined the Stokes vector theory, the expressions of light intensity, the degree of polarization, the orientation angle and the degree of ellipticity on the receiver plane were studied. Furthermore, the effects of diaphragm aperture obscuration ratio on the light intensity, the degree of polarization, the orientation angle and the degree of ellipticity were analyzed. The results show that the light intensity and polarization properties of polarized Gaussian Schell-model beam passing through the aperture exhibit variation with oscillations, and effects of aperture obscuration ratio on them are drastic, especially in the near-field region. Besides, with the increasing of the transmission distance, effects of the aperture on the light intensity and polarization properties are reduced.