Abstract: Spatial uniformity is one of the core parameters of the radiation calibration for imaging spectrometer. Based on the research on the test methods of uniformity at home and abroad, a spatial distribution method was proposed to test the spatial uniformity of the grating imaging spectrometer. The detailed distribution of the signal response at each position was accurately obtained by this method, which was of great significance for improving the image and spectrum quality of the grating imaging spectrometer. The spatial distribution method was established based on the standard light source with high stability and high uniformity, the test results were separated by the computer software, and the spatial uniformity of the grating imaging spectrometer was obtained by extracting the spatial response signal at the same wavelength. Finally, the influencing factors of the spatial uniformity measurement uncertainty were analyzed, and the influence of spatial uniformity on the absolute radiation calibration and the spectral accuracy was analyzed.