介绍了作者在滇西地震预报实验场区进行的土壤中断层气研究结果．沿红河断裂带断层气组分Ｈ２，ＣＯ２，Ｈｇ和Ｒｎ含量很高．沿该断裂洱源测线断层气Ｈ２，ＣＯ２和Ｒｎ含量最低，向南Ｈ２，ＣＯ２含量逐渐升高，其中以定西岭测线的Ｈ２，ＣＯ２含量最高．表明在该段断裂活动强烈，而洱源一带断裂活动较弱． This paper introduces the results of the study on the fault gas in the soil conducted by the author in the area of ​​earthquake prediction in western Yunnan. The contents of H2, CO2, Hg and Rn of fault gas components along the Honghe fault zone are very high. The contents of H2, CO2 and Rn are the lowest along the line of Eryuan fault, while the contents of H2 and CO2 are increased gradually to the south, of which the H2 and CO2 contents are the highest in Dingxi ridge. It shows that there is a strong fault activity in this section, while the fault activity in Eryuan area is weak.