In order to change the physical properties of aqueous solution and improve the radiation intensity of the ICP emission spectrum, the effects of different laser power density and irradiation time on the surface tension and viscosity of aqueous solution were investigated by using near infrared laser at 976 nm and CO2 laser at 10.6 μm to irradiate aqueous solution orthogonally, then the enhancement of ICP spectral intensity with processed solution was discussed. The results showed that the surface tension and viscosity of aqueous solution reduced by 42.13% and 14.03% compared with the untreated, and the atomization efficiency increased by 51.26% at the laser power density 0.265 7 W·cm-2 of 976 nm and 0.206 9 W·cm-2 of CO2 laser with 40 min irradiation time. With the optimized aqueous solution introduced into the ICP source, the spectral line intensity of sample elements As, Cd, Cr, Hg and Pb was enhanced by 46.29%, 94.65%, 30.76%, 33.07% and 94.58% compared to the untreated aqueous solution, while the signal-to-background ratio increased by 43.84%, 85.35%, 28.71%, 34.37% and 90.91%, respectively. Plasma temperature and electron density also increased by 5.94% and 1.18% respectively. It is obvious that the method of double-beam laser orthogonal irradiation on solution can reduce the surface tension and viscosity of aqueous solution significantly, and raise the radiation intensity of ICP source, and will provide a better condition for detecting the trace heavy metal elements in water samples.