Based on the visible near-infrared (VNIR) data acquired by TG-1 hyperspectral imager on March 6, 2012, synchronous and non-synchronous alternative spectral calibration were assessed at the oxygen band. In order to improve the reliability of non-synchronous alternative spectral calibration result, other two images with similar imaging date were used to achieve multiple calibrations. The results show that non-synchronous alternative spectral calibration results based on three images are similar, difference is less than 0.2nm, and standard deviation is less than 0.11. Difference between synchronous and non-synchronous alternative spectral calibration results is less than 0.3nm. Compared with the TG-1 on-board spectral calibration results, the error of the two alternative spectral calibration methods is 0.384nm and 0.489nm, respectively. The accuracy difference is relatively small. Non-synchronous alternative spectral calibration method can be used to achieve high-frequency spectral calibration for hyperspectral imager.