Dual-beam laser induced breakdown spectroscopy (LIBS) is more sensitive than conventional single-pulse LIBS. A combined configuration of Nd:YAG and CW- CO2 lasers is used to improve the emission intensity of LIBS. The plasma of Al sample was observed under CW-CO2 laser and Nd:YAG laser excitation. The enhancement radiation was obtained from dual-beam LIBS rather than single LIBS, which indicated that IR preheating can cause significant enhancement of plasma. The effects of CO2 laser spot size, laser irradiation time and laser power on plasma emission intensity were investigated. And on this basis, the variation of electron temperature and electron density of plasma with delay time is obtained.
