Abstract: ObjectiveThe control effect of 18%2,4-D micro-emulsion(ME) against Mikania micrantha in non-cultivated land was determined to provide references for its application and promotion. MethodFour different treatments of 18%2,4-D ME (540.0, 324.0, 202.5 and 162.0 g a.i./ha) were sprayed on Mikania micrantha leaves at peak growth stage to compare their control effects with recommended levels of common chemical herbicide (glyphosate isopropyl amine salt aqueous solution 1845.0 g a.i./ha) and the control . The coverage of Mikania micrantha before and after spraying 15 and 30 days, and the cover-age and fresh weight of Mikania micrantha after spraying 45 days were measured to calculate the control efficiency. The experi-ment was repeated for two years (2009 and 2010). ResultAll the dosages of 18% 2,4-D ME in the experiments showed great control effects on Mikania micrantha. The control effects of 162.0-202.5 g a.i./ha of 18%2,4-D ME on coverage and fresh weight of M. micrantha in non-cultivated land were 97.74%-100.00%and 98.80%-100.00%on 45th day, which were signifi-cantly higher than that of the control herbicide. ConclusionDue to good control effect, 162.0-202.5 g a.i./ha of 18%2,4-D ME could be recommended to control Mikania micrantha in non-cultivated land.