The finite element code AUTODYN was used to numerically simulate the detonation processes of double layer shaped charges. The shock initiation of the inner layer charge was described by the Lee-Tarver ignition and growth model. Detonation wave propagation processes of the double layer shaped charges were discussed by the numerical results and the corresponding characteristic parameters were obtained. Jet formation processes of the typical single and double layer shaped charges were numerically presented, and jet parameters for the double layer charges with different detonation velocities in the inner and outer layers were numerically analyzed. Calculated results show that the jet head velocities of the double layer shaped charges are higher 20% than those of the single layer shaped charges. Double layer charges can effectively enhance the head velocity of a shaped charge metal jet, augment its penetration depth and increase explosive charge power.