Abstract: By using the beam coherence-polarization(BCP) matrix method, the expressions for the degree of polarization and intensity of nonuniformly polarized(NUP) beams propagating through an annular aperture are derived, which enable to study the changes in the degree of polarization and intensity of NUP beams propagating through the annular aperture. It is shown that, the degree of polarization is usually nonuniform, but is nearly uniform in the central region at the transversal plane, which depends on the NUP beam parameters, obscure ratio of the aperture and propagation distance. The uniform intensity of NUP beams becomes non-uniform with a central principal maximum and small diffraction side lobes after passing through the aperture.