Invasive, alien plants pose a serious threat to biodiversity and the sustainable development of agricultural and forestry. The spread of invasive plants is closely related to their evolutionary response to herbivorous insects in novel habitats. This article provides a systematic review of the evolution of the defense strategies of invasive plants and their ecological effects of these, focusing on chemical defense, physical defense, and volatile-mediated defense. In terms of chemical defense, invasive plants exhibit evolutionary shifts in both qualitative and quantitative defenses, enabling them to precisely balance the costs and ecological benefits of defense. Physical defense traits, such as increased leaf thickness and higher trichome density, are significantly enhanced and play multi-functional roles in both stress resistance and insect defense. Volatile-mediated defenses reconstruct multi-trophic interaction networks, influencing the behavior of herbivorous insects, the recruitment of natural enemies, and pollination efficiency. Finally, this paper proposes that future research should prioritize four key areas: The molecular regulatory mechanisms underlying defensive trait evolution, patterns of co-evolution within multi-trophic interaction networks, the potential application of specialist natural enemies in biological control, and the impact of global climate change factors. Further research on these areas will provide a theoretical basis for developing invasion management strategies grounded in ecological interaction principles.