Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method.The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated gratings and a metal reflector sandwiching a SiO2 thin layer which appears promising for high spontaneous emission enhancement devices.Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reach an ultra-high near-field enhancement factor in the excitation process.Moreover,concerning the emission process,the corrugations concentrate the far-field radiated power within a tiny angular volume,offering unprecedented collection efficiency.In the past decades,many kinds of optical antennas have been proposed and optimized to enhance single molecule detection.