The influence of supermolecular structure on the mechanical properties of linear polyethylene has been studied. The change in film structure has been realized by means of variation of isothermal crystallization conditions. The films obtained had either lamellar structure, or consisted of spherulites. It has been shown that the tensile strength of unoriented films with small spherulite structure is twice as great as that of films with well developed lamellae. This mechanical difference remained after 20‐fold drawing of the specimens at high‐temperature (102°C) for short times. The study of the structure of oriented films showed that in all the cases the transverse size of microfibrils remained constant. However, with the help of infrared spectroscopy it has been found that the amorphous phase orientation here was different, while the degree of elongation was the same.