In order to study the propulsion performance of metals ablated by nanosecond laser with 532 nm and 1 064 nm wavelength, 8 ns and 15 ns fundamental frequency, the mass removal, specific impulse, momentum coupling coefficient and laser energy coefficient of metals were measured under background pressure of 40 Pa. The results show that the mass removal of iron is largest, while yttrium has the lowest mass removal. The mass removal of metals during laser ablation is determined by laser absorption, melting point and boiling point of metals. Under conditions of larger power density(＞2.71×1010 W/cm2), the specific impulse and laser energy coefficient of yttrium are largest, while the iron has the lowest specific impulse and laser energy coefficient. The changes of metal ablation characteristics are explained by mechanisms of ground state atoms excited to form plasma and irradiation laser shielded by plasma. The research is helpful to selection of metals using for laser ablation.