[en] We have proposed an approach to use a gamma-ray for nuclear transmutation by Compton scattering of laser photons with high current accelerator. We demonstrated laser Compton scattering to obtain 20 MeV gamma-ray to address transmutation rates with the giant resonance of ¹⁹⁷Au and ¹²⁹Iodine. Experiments for measurements of neutron spectrum and pair production were performed for energy balance of this scheme and for target conditions. The results showed reaction rate was about 2-4% for appropriate photon energies and neutron energy was up to 4 MeV in the calculation