Deformation-induced structural evolution of polyethylene (PE) gel films were investigated by in situ synchrotron radiation SAXS and WAXS techniques during stretching at temperatures from 25 degrees C to 110 degrees C. The structural evolutions along tensile strains showed distinct behaviors in the four temperature regions divided by T alpha I and T alpha II given by DMA and the onset point of melting measured by DSC, respectively, which was determined by the coupling effects of external stretching field and temperature. Finally, the morphological diagrams of PE gel films on distinct scales including long period of lamellae, crystallinity, and crystal size in 2D temperature-strain space were established, which can give a direct sight of membrane morphologies and act as a map for processing parameters selection. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 748-757