Abstract: A double scintillator fast neutron TOF spectrometer are constructed. It consists of alpha counter, scatterer detector, neutron detector, shiclding collimator system and electronics. It are used to measure 15.2 MeV and 13. 6 MeV neutron elastic scattering angular distributions and D (n, 2n) reaction emitted neutron double differential cross sections from deuterium. The principle, apparatus, main performance and applications of the spectrometer are presented in the paper.