Development of deformation and rupture for a cylinder shell under high-pressure explosion loading is very important in. dealing with the direct accelerating and kill effect of the shell. The paper assumes the shell material as rigid and perfect plastic. The stress field，deformation speed，breaking radius and fragment velocity are approached. Comparison with experimental data has been made for 50 kinds of copper shell and 11 kinds of steel shell filled with various explosives. All the results are in good agreement with the data. The relative deviations are 3% or so. The new model is suitable for engineering calculations.