Abstract: Thermal-mechanical failure behavior of the internally pressurized cylinder shell under laser irradiation is investigated by numerical approach. The dynamic bursting processes are simulated, and the obtained failure modes are validated by experiment. Three typical failure modes are found and the corresponding parameter ranges are listed, and formation mechanisms of each failure mode are discussed. The effect of thermal softening on the threshold of internal pressure at different laser spot sizes and shell thicknesses are explored, and the relation between internal pressure and failure time is discussed. The results show that the threshold of internal pressure decreases with the increasing laser spot size and the extent of thermal softening, and it is in linear relationship with the shell thickness. At given laser parameters and shell parameters, the failure time declines in a quadratic function of internal pressure. A method to predict the failure time of internally pressurized cylinder shell under laser irradiation based on thermal softening factor is proposed and presented.