Wedelia trilobata was a native of Middle and South America.At the present.,the invasive plant endangers the agriculture and forestry production,and even destroys the ecosystem and bio-diversity.Researches on its responses to herbicides and measures to control it were initiated.Results showed as follows:(1) Leaves of cultivated W.trilobata treated with different concentrations of herbicides showed various extent injuries and the injury could be intensified as the concentrations increased.W.trilobata treated with 1:200 to 1:600 picloram and clopyralid and 1:200 to 1:800 fluroxypyr solutions were totally killed.(2)W.trilobata showed significant reduction in chlorophyll content after treatment with the herbicides,positive correlation between the concentrations of application and the injury to was observed.(3)After treatment,the cell membrane permeability of the plant was increased,which proved due to damage.(4)Treatment in field showed that three herbicides in combination could kill the plant at 1:600 picloram and clopyralid in 10 days,or 1:800 fluroxypyr in 15 days.