Abstract: In the paper a method is introduced which is used to produce discretegamma rays in 5-10 MeV region by means of a～10~5n/s Am-Be neutron sourcethrough the radiation capture process. High energy monochromatic gamma rays with low level background areproduced utilizlng resonance scattering on Pb of gamma rays from the Fe (n, γ)reaction induced by the reactor thermal neutrons. The device is very simple and can conveniently be used for the energycalibration and relative efficiency determination of various gamma rays detectorssuch as Ge(Li), HpGe, NaI(Tl), BGO, etc.