In order to improve the spectrum quality of laser-induced plasma,the effect of CsCl additive to soil sample on the radiation characteristics of plasma is studied.Nanosecond pulse laser is used as the excitation source.The experimental results show that the CsCl additive can obviously enhance the radiation intensity of the plasma under the condition that the laser energy is 200 mJ.When the CsCl with amount of 20% is added,the spectral intensities of elements Al,Fe and Ti are increased by 42%,39% and 54% compared with the soil without additive,while the spectral signal-to-background ratios increase by about 8%,24% and 28%,respectively,and the widths of the spectral lines of elements Fe and Ti become narrow.Besides,the plasma spectra induced by 300 mJ and 400 mJ laser energy are also studied.