Abstract: The material mass ablative law of the carbon fiber epoxy composite irradiated by continuous wave Nd∶ YAG laser was researched by experiment. The results indicate that the composite ablative mass is directly proportional to the laser radiation energy when the laser radiation intensity is greater than 10 kW/cm²；with the same laser energy radiation , the mass ablative rate at high intensity of 0.65 mm laser spot radius is nearly twice that at low intensity of 5.5mm laser radius；combustion phenomena cause the mass ablative rate to fluctuate when the irradiation laser power is near the composite burning threshold.