The objective of this study is to define the effects of Tephrosia vogelii (T.vogelii)soil on the red imported fire ant (RIFA,Solenopsis invicta Buren).The behaviors including mortality, grasping and walking ability and lethal effect activity of the soil to RIFA were researched by rotenone.Rotenone exerts a defimite toxicity to RIFA.As we know, T.vogelii leaves contain rotenone and are now widely used to prevent RIFA as a source of botanical pesticides.In this study rotenone in T.vogelii leaves which was classified as different position and ages and soil of different depth and distance, was identified by high performance liquid chromatography (HPLC).The content of rotenone slightly varied in different leaf positions ranged from 0.124% to 0.144% and increased with leaf age (0.09%-0.565%).The soil extract was detected and showed that it contained a small quantity of rotenone and decreased with depth (0.004%-0.368%) in the soil at depths of 0-20 cm.In the insecticidal toxicity bioassay, the corrected mortality of major workers treated with the soil at depths of 0-20cm increased from 0 to 92.00% with contact time from 1-5d and that accords with the increase of rotenone.In the crawling ability bioassay, the crawling rates (17.00%) of major and minor workers treated with T.vogeliisoil at depths of 0-20cm for 12-60h.were significantly lower than the control group.Corrected grasping rate of minor and major workers in the rotenone soil with different depth in the insecticidal activities bioassay for 12-60h ranged from 19.33%-95%.The results showed that T.Vogelii soil had ecological value of effectively prevent RIFA.Perhaps we could control the RIFA by planting cinnamon in some areas.