A series of titanium dioxide/silicon dioxide based poly(ethylene terephthalate) (PET) polycondensation catalysts were synthesized with different Si/Ti molar ratios and various amounts of polyvinylpyrrolidone (PVP). The composition, structure, and catalytic activities of the catalysts and the properties of the PET samples catalyzed by these catalysts were characterized with thermogravimetric analysis, electron probe microanalysis, X-ray diffraction, Xray photoelectron spectroscopy, and so forth. The results indicated that the Si/Ti molar ratios of the catalysts could be well controlled by the synthesis processes used in this study, whereas the content of PVP was influenced by the amount of titanium dioxide. The activities of the catalysts greatly depended on the Si/Ti molar ratios and coordinative effects between titanium and PVP. Some of the catalysts possessed ultrahigh activities, and the corresponding PET material had excellent properties. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2470-2478, 2010