The temperature spectra of the dynamic mechanical properties of Nylon-6 monofila-ments of different draw ratios and with α，γ and γ+α forms of chain conformation in the crystalline region，were determined over a temperature range extending from一150°to + 170℃ by using the resonanting reed method in audio frequencies．In addition to the three internal friction peaks known in the literature，i.e. 一110℃(βα)，一40℃(β'α) and 50℃(αα)，a new loss peak at 130℃ was observed for Nylon-6 in γ-form containing monomer and oligomers．According tO the experimental results，the temperature of α-peak for samples in α-form is higher than those in γ-form，that means that chain segments in the γ-form have higher mobility than those in the a-form．The loss peak β'α was greatly enhanced when iodine was absorbed in the fibre．This supports the view that the β'α peak is connected with the motion of chain segments containing free amide groups．The β'α-peak also grows rapidly with orientation，indicating the possible breaking up of hydrogen bonds during the stret-ching process．The new internal friction peak ac was found in γ-forms only．The peak height decreased rapidly with increasing draw ratio and vanished at a draw ratio of 3.8. Experi-mental results indicate that the ac 1088 peak is due to molecular motions of the segments in the crystalline region in γ—conformation．