Provided are an insecticide and a preparation method therefor. The insecticide is composed of the following formulation components in parts by mass: 10-20 parts of wormwood juice, 6-8 parts of arsenic trioxide, 5-7 parts of methamidophos, 10-12 parts of Crocus sativus, 6-8 parts of chlorfluazuron, 4-6 parts of allicin, 10-20 parts of chilli juice, 5-15 parts of Artemisia argyi juice, 10-12 parts of Geranium wilfordii, 5-15 parts of Artemisia tridentata bark, and 1-3 parts of avermectin. The preparation method is simple. The effect of killing scale insects is significant. The insecticide has no toxic side effects for humans and livestock, does not pollute the ecological environment and is a low-toxicity, safe and environmentally friendly green insecticide.
