Based on the beam coherent-polarization matrix approach and propagation law of partially coherent beams, the propagation properties of partially polarized Gaussian Schell-model beams diffracted through an aperture in the far field are studied. Detailed numerical calculation results and physical analysis are presented and illustrated for the far-field polarization and intensity properties. It is shown that the far-field behavior of diffracted partially polarized Gaussian Schell-model beams depends on the truncation parameter, spatial coherence parameters and diffraction angle. The corresponding results for the unapertured case are given and a comparison with the previous results is also made.