Abstract: Resolution is an important parameter of a grating spectrometer.However,because the spectrometer is a highly integrated instrument,the experimental teaching around the spectrometer often focuses on teaching students how to use the spectrometer;it makes it difficult for students to intuitively establish the relationship between resolution and slit width.In this paper,based on the structure and working principle of WGD-8A multifunctional grating spectrometer,the 656.11 nm and 656.28 nm double lines of hydrogen deuterium lamps were used to measure the hydrogen enthalpy lamp 656.11nm and 656.28 nm under different incident slit widths and exit slit widths.It is demonstrated that the resolution of the grating spectrometer decreases with the slit width increase,and it is more sensitive to the variation of the exit slit.In order to achieve the test resolution of spectrometer,the entrance slit width shoule be set around 0.35 mm,and the exit slit width should be set the within 0.18 mm.