Abstract: A catalytic composition for preparing a polyethylene terephthalate (PET) resin is provided. The catalytic composition comprises a polycondensation catalyst and cesium tungsten oxide (CsxWO3-yCly), and 0<x?1 and 0?y?0.5. A PET resin prepared by the catalytic composition above is also provided. The PET resin comprises 2-80 ppm of cesium tungsten oxide. This catalytic composition can solve the problems of slow solid-state polymerization rate of the PET preparation and thus the long preparation time, as well as yellowing. Moreover, the PET resin can absorb infrared radiation.