The frame of membrane electrode assembly (MEA) influences the durability of proton exchange membrane fuel cell (PEMFC). In this paper, the thermal shock bench was applied as an accelerated aging test to explore the effect of frame sealing structure on MEA durability at different temperatures. Analysis of scanning electron microscope (SEM) images reveals that thermal shock results in the formation of cracks on the exposed proton exchange membrane (PEM) at the gap between the frame and the active area. Moreover, it breaks the bonding interface between the frame and the membrane and leads to the debonding of the adhesive, which exacerbates the risk of crossover of the reactant gas. A comparison of the single-layer and improved double-layer frame structures reveal that the mechanical damage is caused by frequent membrane wrinkles in the gap under temperature shock. However, addition of a cushion layer improves the continuity between the frame and the active area, and reduces deformation of the membrane, thereby preventing membrane damage.