The vermiculite(VMT) was treated at high temperature or by microwave and modified by treatment with different intercalaling agents:reagent A, which was synthesised in our lab, hexadecyl trimethyl ammonium chloride and octadecylamine to give organo-vermiculite(OVMT). The polyethylene terephthalate(PET)/vermiculite composite was obtained from OVMT with in situ polymerized PET. The cation exchange capacity of VMT was found increased apparently after chemical treatments. The spacing of layers in VMT was increased to 4.65 nm after intercalation with different organic reagents. The structure of PET/VMT nanocomposites synthesized was studied by FTIR、 XRD and TEM. The DSC results showed that the PET/VMT nanocomposite has T g of 137.16 ℃ and melting point of 235.76 ℃.