Abstract: Using laser in centimeter scale space debris removal has important application prospect. Impulse coupling characteristics of laser ablated material of space debris was experimentally studied. Laser of 532/1 064 nm wavelength and 8/15 ns pulse width were used in experiment, and aluminum as the ablation target. Torsional balance system was used to measure impulse, and influence of laser parameter on impulse coupling coefficient was studied. Experiment results show that impulse coupling coefficient of Al shows a trend from rise to decline, and exists the optimal value. When ablation depended on gasification mechanism, decrease wavelength or increase pulse width can effectively improve impulse coupling coefficient; When ablation depended on ionization mechanism, plasma shielding effect of 532nm laser is weakened, achieving the optimal impulse coupling coefficient on initial formation of plasma.