Damage mechanism of shells with inner pressure that are exposed to high power CW CO2 laser is studied here. The physics model and numerical solution model of thermal and mechanical responding is described. The finite element method is used to simulate nonlinear temperature and stress profile. Two types of shells are considered and the laser power density is varied from 400 W/cm2 to 1500 W/cm2. The damage times are presented and the damage areas are plotted.