The similarity law of the detonation wave and the plastic deformation of the structure are considered and equivalent assess method for the local damage of the real ship through distortion model in penetration explosion experiments of the large scale model is studied.Through penetration explosion simulation analysis on four kinds of scale experimental scheme and the summary of error of real damage results

it can be concluded that when scaled ratio λ is 0.25 and distortion coefficient φ is 2.5

the local damage of original model can be assessed accurately by the model experiments within appropriate engineering application which meets the manufacturing production and the economic demand.The conclusion can provide application references to the penetration explosion experiments of the large scale model.