The study of UV laser induced damage dynamics is the key to exploring correlating evolution of optical elements’ microstructure and macroscopic properties. In optical elements damage process on the rear surface, the laser energy deposition causes the material to explode with high pressure and high temperature to break through the rear surface, and it is accompanied with explosion plume and jet particles. The explosion plume is greatly affected by the initial laser energy deposition. The study of the explosion plume can help a lot in analyzing the material state change and response mechanism at the initial stage of damage. In this paper, explosion plume on the rear surface is investigated using a two-color interferometric time-resolved side-viewed imaging system. Assisted with the observation of the collected ejection, the material species, distributions and thermodynamic behaviors of ejections are presented. Based on findings, the key transition nodes of the response behaviors during laser induced damage formation are captured and the temporal evolvement of plume is described.