采用YJG-Ⅱ激光微区分析仪、组合式多功能光栅光谱仪和CCD数据采集处理系统构成的激光微等离子体光谱分析系统，以国家标准土壤样品(BGW07411)为样品，在Ar，He和不同He-At混合的环境气氛下，以CaⅡ393.367nm，CaⅡ396.847nm为分析线，实验研究了土壤激光微等离子体辐射强度。研究结果表明，He-Ar混合气氛环境等离子体发光时间、辐射强度均好于单一He，Ar环境气氛。当He-Ar混合气体分别为：He66.7％，Ar33.3％时，等离子体辐射强度明显增强，并在此条件下研究了辅助电极高度对激光微等离子体辐射强度的影响。当辅助电极高度为3mm时，激光微等离子体的辐射强度达到最佳。

The plasma radiant intensity was investigated by a laser micro-plasma spectral analysis system. The system consists of an YJC- Ⅱ laser micro-spectral analyzer and a CCD data acquisition and processing system. National standard soil samples were studied in the experiment under different ambient atmosphere with argon, helium and the mixture of argon and helium by using the analysis lines, CaⅡ 393. 367 nm and Ca Ⅱ 396. 847 nm. The results of this research suggest that both the time of plasma illumination and the radiant intensity of plasma in an atmosphere of helium argon mixture were better than that in pure helium or argon gas. The plasma radiant intensity was obviously enhanced when the proportion of helium and argon was 66. 7% and 33.3%, respectively. Under these conditions, the influence of the height of auxiliary electrode on laser micro-plasma radiant intensity was also investigated. The maximum laser micro-plasma radiant intensity was reached when the height of auxiliary elec trode was 3 mm.