The experiment was carried out for vegetable crops protection to insect pests by using weeds at which natural enemies attract or argument through eating insects on weeds, and can migrate to vegetable crops. Erigeron annuus(Linne) Persoon was the weed, which showed the most insect populations among different weeds around agricultural area. There were Uroleucon (Lambersius) erigeronense (Thomas, 1878) as a herbivore, and Harmonia axyridis as predators and Aphidius sp. as a parisitoid on the E. annuus. Harmonia axyridis from E. annuus showed the peak population on June 2005. Hibiscus syriacus Linne was one of the important trees with natural enemies including a lady beetle. Cotton aphids showed the highest population on H. syriacus on May 18, and Lady beetles showed peak density there on May 20, 2005. It is suggested that natural enemies on weeds will migrate to crops and will be helpful for insect pests control on the vegetable crops.