Pulse compression based on laser-induced optical breakdown in suspension is investigated.The physical mechanism behind it is analyzed theoretically and validated in the Q-switched Nd:YAG laser system.A 12-ns pump pulse is suppressed to 5 ns with good fidelity in the front edge and sharp steepness in the trailing edge.The HT-270,which has a small gain coemcient and absorption coefficient,is used as a solvent,and therefore the disturbance induced by stimulated Brillouin scattering and absorption are minimized and the transmittivity is enhanced.