Abstract: The energy resolution is an important index for simulation and calculation in the design of neutron spectrometers. In this paper, the working principles of neutron triple axis spectrometer and neutron multi-channel spectrometer were illustrated. With MCSTAS software, the neutron tracing models of the two spectrometers were built, and the quantitative calculations of the energy resolution in different neutron incident and final energy were completed based on the simulation results. The multi-channel spectrometer has relatively low energy resolution comparing with triple-axis spectrometer because of the variation of scattering plane. However, the variation of scattering plane could optimize the special arrangement of analyzers and detectors in multi-channel system. Through analyzing the simulation results, the appropriate collimator types were given in order to improve the energy resolution of multi-channel spectrometer.