The influence of the melt temperature on the crystalline morphology of polytetra-fluoroethylene was studied by Small An．gle Light Scattering and Electron Microscope techniques． When PTFE was melt．crystallized from temperature below 400℃ under slow cooling rate

the rodlike morphology was obtained；when it Was crystallized from temperature above 455℃．the spherulitie marphology was formed．From the inteme-diate temperature range，the formed sheaflike morphology can be viewed under electron microscope：The DSC study shows that the change of morphology with melt tempera-ture is due to chain seission of macromolecules．The decrease of molecular weight of PTFE with heat-treat temperature was estimated by the measurement of heat of crystal-lization using Suwa’s relation and the deterioration of meehanieal property with the increase of heat-treat temperature was also notieed．