The effect of spectral-line shift on radiometric measurement accuracy of spaceborne imaging spectrometer during laboratory radiometric calibration, onboard radiometric calibration and onboard radiometric measurement is analyzed. Radiometric transmission model from laboratory radiometric calibration to onboard radiometric measurement has been established, and relationship between the uncertainty of radiometric measurement on entrance pupil and spectral-line shift is simulated. Results show that radiometric measurement error is linear to spectral-line shift and radiance distribution gradient on entrance pupil of imaging spectrometer. The radiometric measurement error caused by spectral width deviation is one order of magnitude larger than that caused by central wavelength deviation. For a typical imaging spectrometer [10 nm spectral width in visible near infrared spectroscopy (VNIR) band and 20 nm in shortwave infrared (SWIR) band], central wavelength deviation is less than 2 nm and spectral width deviation is less than 0.1 nm in VNIR band, or central wavelength deviation is less than 3 nm and spectral width deviation is less than 0.1 nm in SWIR band, which is necessary to ensure the uncertainty of radiometric measurement caused by spectral line-shift less than 6% and absolute accuracy of radiometric measurement on entrance pupil is superior to 10%.