Based on the vectorial Debye theory, the tight focusing properties of partially coherent and circularly polarized vortex beams are investigated. The focused characteristics of right-circular and left-circular polarized partially coherent vortex beams in the focal region are presented and compared by some numerical calculation results. Furthermore, the influences of the source coherence and the numerical aperture of the focusing objective on the tight focusing properties are studied in great detail. It is shown that the coherence and polarization properties of the focused left-circular polarized beam is less influenced by the source coherence and the numerical aperture of the focusing objective than that of the focused right-circular polarized beam. By selecting certain parameters, the widely used flat top beam can be obtained.