A rotating single crystal thermal neutron time of flight spectrometer was constructed in IAB for the study of various dynamic process in condensed matter. The surplus reflections from undesired crystallographic planes in the rotating monochromator (Ge) is eliminated by carefully choosing a proper orientation of the rotating axis in the (Ⅲ) plane. The range of incident initial neutron energy is from 10 meV to 100 meV; The corresponding energy resolution is 2.5 to 7.2% with intensities adequate for inelastic scattering studies. Based on the work of Brockhouse et al., we have calculated a theoretical value of the resolution for neutrons scattered from the sample and compared it with measured results. Inelastic neutron scattering spectra from vanadium sample is presented and comparison with other spectrometers of similar type is given.