We report an improved light extraction in all-inorganic perovskite light-emitting devices (PeLEDs) by integrating a periodic corrugated nanostructure at the metallic cathode/organic interface. Nanoimprinting lithography was used to introduce the nanostructures onto the surface of the electron transport layer directly to avoid influencing the morphology and crystallinity of the perovskite film underneath. The trapped energy at the metallic electrode has been successfully outcoupled by the excitation of the surface plasma polariton (SPP) modes induced by the periodic corrugations. The luminance and current efficiency of the periodically corrugated PeLED exhibit enhancements of 42% and 28%, respectively, compared to those of the planar PeLED. The finite-difference time-domain simulation was used to confirm the efficient outcoupling of the SPP modes.