In this paper，we use the α-relaxation in dynamic mechanical behavior of poly (ethylene terephthalate (PET) as a probe，to detect the difference in the state of mole-eular aggregation of PET in the amorphous region under various conditions of draw-ing．Our studies show that，the quite different state of the amorphous regions of ori-ented PET samples can be obtained by variation of the speed and temperature of drawing，and the state of their amorphous regions is clearly demonstrated to be different by their a-peaks．Because the position，height and shape Df the a-peak in mechanical-10ss(Tan δ)-temperature curve reflect the intermolecular interactions and hence the state of the amorphous region of oriented PET sample，so that，those parameters show rea-sonable correlation with other mechanical behaviors and gome structure parameters of the PET sample．Furthermore，the experimental results show that there is an Arrhenius type equiva-lence between the draw speeds and the draw temperatures of samples with similar amorphous state．