This study was carried out to investigate the introduced route of exotic weeds and the effects of herbicide treatment. Herbicide trial was arranged as a completely randomized block design with treatment 1(circled1 Dicamba $1ell$/ha, circled2 Mecoprop $5ell$/ha, circled3 Bentazone $3ell$.ha, circled4 Glyphosate $4ell$/ha and circled5 Pyrazosulfuron-ethyl 2kg/ha), and treatment 2(circled1 Dicamba $2ell$/ha, circled2 Dicamba $4ell$/ha, circled3 Glyphosate $6ell$/ha, circled4 Glyphosate 4+Dicamba $1ell$/ha and circled5 Glyphosate 4+dicamba $2ell$/ha) against 10 exotic weed species, and conducted in Suwon, Seosan and Yeongam from 1997 to 1999. Exotic weeds have been mostly introduced within imported cereals for concentrate feed or within seeds for forage production. Most of exotic weeds in forage crop field were controlled more than 95% by herbicide, but it was desirable that the control of exotic weeds was abreast of chemical and ecological method.