Abstract:The Mikania micrantha H.B.K., a native to Central and South America, has becoming a noxious exotic invasive weed in the seashore areas in Guangdong Province and its neighbor Hong Kong, south China, especially in the Neilingding Island of Shenzhen City. In this paper, 9 plots and 81 sub-plots were selected as examples to study and control the invasive of Mikania micrantha in the different habitats and communities in the Neilingding Island. The test result shows that between concentration in 0.0001~0.2 g•m-2 of chemical herbicide sulfometuron-ethyl, the best result could be obtained in controlling Mikania Micrantha; Moreover, the effect of controlling Mikania Micrantha will be much strengthened as the increase of the dosage of chemical herbicide sulfometuron-ethyl. For instance, the sulfometuron-ethyl with the concentration at 0.05-0.1 g•m-2 and 0.2 g•m-2 in the sloping and valley examples could show an effective result. In addition, a new method of distilling sulfometuron-methyl from the soil samples has been excogitated, and it has been used to determine the remnants of sulfometuron-methyl in the examples with Mikania Micrantha in Neilingding Island. Through the testing, it shows that half-life in the valley examples is C=C0•e-0.083T, T1/2=8.4 d, after 37d medicine used, however, it has decompounded 95.9 %. In sloping examples, its half-life of the higher concentration group is C=C0•e-0.046T, T1/2=15.1 d, after 37 d, it has decompounded 85.0 %; and its half-life of lower concentration group is C = C0•e-0.090T,T1/2=7.70 d, after 15 d , it has decompounded 74.2 %. From these samples, we found that the decompounding speed of sulfometuron-ethyl are very fast and quick, and it could be determined after using medicine for 7, 15 d, and 37 d, since its content became smaller than it was before. However, with HPLC examination in the different concentration and condition, there is no any sulfometuron-ethyl in the soil samples after using medicine for 68 d.