The phenomena in ablation process of Nd:YAG laser irradiating carbon fibers reinforced epoxy resins composites under different intensities were observed by high-speed camera. Below low intensity (50 W/cm2), composite material laser ablation is dominated by surface ablation mechanism rather than burning, and the surface slight decomposing leads to form carbon powder or flocs which slowly disperse into the air under long time irradiation; At middle intensity of 300 W/cm2 composite material laser ablation is dominated by volume ablation mechanism, inner decomposition gases spill into the air and ignite surface combustion; At high intensity 4500 W/cm2 the main mechanism of the mass ablation is surface ablation, surface layer is damaged and instantaneously burns in a very short time (0.001 s), jet of plasma forms in the center of laser spot, anisotropic heat conduction causes layered ablation and deforms the ablation zone appearance.