A simulation blanket assembly consisting of depleted uranium and LiH is established for studies on fusion-fission hybrid energy reactor.The leakage neutron spectra from a directly current D-T neutron source placed in the blanket assembly were measured by BC501A spectrometer in the 0.75–16 MeV energy range.The measured leakage neutron spectra were compared with the results calculated by the 3D Monte Carlo code MCNP5 and continue energy cross sections from the ENDF/B-VI data file.The comparison shows that the MCNP5 code with appropriate data library can reasonably approximate the measured leakage spectra of neutrons.