Abstract: In terms of phenomena of the experiments and measurements from the tests,based on the penetration equations,referred to Young's thought,a calculation method of "linear deceleration model" for a projectile impacting concrete targets is presented.The deceleration curves of a projectile impacting concrete targets are thus calculated.To verify the results of former method and the present method deceleration tests were conducted for the perforation of a projectile against multi-plates concrete targets and penetration of a projectile against half-infinite concrete targets by use of an on-board recording system.Predictions of present method showed good agreement with measurements from the tests.