The invention relates to a high-efficiency low-toxicity complex insecticidal agent composed of clothianidin and abamectin. The insecticidal agent is especially used in application researches of rice planthopper controlling. The synergetic insecticidal composition containing clothianidin and abamectin is characterized in that: the composition contains effective and active components of clothianidin and abamectin; and the composition contains components of, by weight: 0.1 to 50% of clothianidin, 50 to 0.1% of abamectin, and balance of auxiliary components allowed and acceptable in pesticides. The insecticidal composition provided by the invention is used for controlling heteroptera, coleopteran, diptera, some of lepidoptera, and other pests such as aphids, leafhoppers, thrips, and planthoppers on rice, vegetables, fruit trees and other crops. For example, the insecticidal composition can be used for controlling planthopper, rice leaf folder, striped rice borer, myzus persicae, green peach aphid, pear psylla, whitefly, and the like.