Distributive characters of hypervelocity fragments impacting double-level target were researched.The uniform distribution model of fragment cloud was presented under certain reasonable hypothesis for engineering calculation according to the principle of surface energy equal to local inertia or kinetic energy during breaking process.Based on the law of conservation of energy

fragment size

mass distribution

fragment quantity and the fragment movement law are obtained.And the parameters of fragment cloud may be promoted to supply the design foundation for the protection and wreck of spacecrafts.