The ionospheric space environment is complicated, and the ultraviolet-band light energy is feeble. Therefore, an important part of the study of the far ultraviolet ionization layer hyperspectral load is understanding how to suppress the stray light of a far ultraviolet hyperspectral imager. As per the system technical requirements, this paper presents a stray-light suppression method for a single toroidal grating hyperspectral imager. To evaluate the stray-light suppression effect, we first examined the main sources and propagation paths of stray light, then designed a structure for stray-light elimination using the UG software, and finally used the LightTools software to simulate the energy response of the receiving surface under various fields of view and grating diffraction levels. The results demonstrate that the difference between the stray light energy out of the field of view and the light energy in the field of view is 10^-5-10^-7, and the difference between the non-working diffraction level light energy of the grating and the working level light energy is 10^-6-10^-8, and the spectral stray-light coefficient at the central wavelength is 0.9975%, indicating that the proposed method meets the requirements of far ultraviolet hyperspectral remote sensing in space.