We report grating amplitude dependence of electroluminescence (EL) in organic light-emitting devices with one-dimensional corrugated structure. Our proposed devices can emit light from both the top silver and bottom quartz side, and both exhibit amplitude-dependence EL enhancement. The effect of grating amplitude on the EL intensity has been studied experimentally and numerically to find out the optimal grating amplitude for the greatest EL enhancement. We deduce from the numerical simulations and experimental results that surface plasmon-polariton modes and waveguide modes are coupled out of the corrugated devices efficiently at the optimal amplitude; therefore, higher efficiency of light extraction could be realized.