In the long-term process of evolution, both host plants and herbivorous insects form a series of complex defense and anti-defense strategies. In this paper, these strategies are classified into three levels. First, host plants perceive herbivoreassociated molecular patterns (HAMPs) and then lead to HAMPtriggered immunity (HTI). This defense is effective against some populations of the herbivore species that cannot secrete effectors. Second, some populations of the herbivore species secrete special effectors to suppress HTI in plants, thereby resulting in herbivore colonization. Third, the effectors of certain populations of the herbivore species could be recognized by resistance genes of host plants, leading to effective effectortriggered immunity and resistance to the herbivore. The elucidation of the mechanisms underlying molecular interactions between host plants and herbivores will not only deepen the understanding of the coevolution between plants and herbivores, but also provide important technical guidance for the breeding of resistant crop cultivars.