Abstract: The ballistic characteristic and the residual velocity of the column(or cubic)fragments(weight: 3.3g~60g)are discussed in this paper after high-speed(velocity: 800m/s~1800m/s)perforation of the warship structure's steel target(thickness: 4mm~10mm). An analysis model is proposed, in which the energy loss of fragments in the penetrating course is transmitted into the strain energies of steel hull due to the compression deformation and annular shear plastic deformation. Based on the conservation of energy and De.Marre model, a semi-empirical formula based on experiments is given. The coefficients in the equation are obtained by numerical data fitting of 32 group test results. The semi-empirical formula is proved to be efficient and reliable by comparision between experimental and calculation results.