The cucurbitacins, as the secondary metabolites, were the oxygenated tetracyclic triterpenoids which produced from the family Cucurbitaceae. More than 100 species from about 30 genera generate such peculiar secondary metabolites. As the bitter and toxic allomones, cucurbitacins protect the plants from the attack by a variety of herbivores and pathogen. On the other hand, as the kairomones, cucurbitacins attract phytophagous insects to the host plants. The complex relationship between the Cucurbitaceae plants and the herbivores, which based on the special chemical properties and biological activities of cucurbitacins，has been widely studied. In this review, we summarized the distribution, the chemical structures and the biosynthesis of cucurbitacins. The defense mechanism of Cucurbitaceae plants against herbivores and pathogen by cucurbitacins was focused. Moreover, the benefit and the future prospect of applicating the cucurbitacins in integrated pest management were discussed.