Abstract: Carbon fiber reinforced composite laminates exhibit three damage phases in drop-weight impact tests and quasi-static indentation tests.There are two knee-points between the three phases.One is delamination and the other is damage.In this paper,three-dimensional(x stands for impact energy,y stands for dent depth and z stands for delamination area) point of the knee-point of damage is employed to characterize the damage resistance and inner-damage of the composite.