Transparent crystal luminescence at impact loading is closely related to its microscopic damage and structure change. The multichannel radiation pyrometer with light-gas gun and spontaneous spectroscopic system are combined to study the light emission of shocked sapphire. The light spectrum of sapphire range is obtained in 400-800 nm wavelength. The spectral distribution exhibits typical thermal radiation characteristics. The radiation temperature is in agreement with the corresponding melting temperature. The mechanism of the luminescence of the sapphire shear band is studied in combination with the radiation temperature and the spectral distribution.