The hyperspectral imager is a new type remote sensor which can collect both the image and the spectral information of the scene. The objective of the spectral calibration of the hyperspectral imager is to determine the central wavelength and spectral width of each channel. The spectral sampling interval of the hyperspectral imager calculated and the atmosphere absorption of the atmosphere were used to calibrate the central wavelength and spectral width of the channels of the hyperspectral imager in the present article. Comparison was made between the spectral calibration result and a spectrometer which has high spectral resolution and the results were improved. The results indicate that the spectral calibration of this method can achieve precision of 1 nm.