The spontaneous spectroscopic and radiation pyrometer techniques are combined together to study the light emission of shocked sapphire and its time dependence under a compression of 41—87 GPa. The results are confirmed that the shock induced light emission from sapphire can be attributed to the thermal radiation from the shear bands because of partial dislocation damage. The spectral distribution matches well with the equilibrium thermal radiation of Planck grey-body feature. The fact that of the radiation color temperature is close to the corresponding melting temperature can be explained reasonably by the thermal equations of the plastic flow.