Climate change will cause drastic fluctuations in agricultural ecosystems, which in turn may affect global food security. We used ecological niche modeling to predict the potential distribution for four cereal aphids (i.e., Sitobion avenae, Rhopalosiphum padi, Schizaphis graminum, and Diurphis noxia) and their three natural enemy insects (i.e., Harmonia axyridis, Episyrphus balteatus, and Aphidius gifuensis) in China’s farmland under current and projected climate scenarios. Due to climate change, the suitable areas of D. noxia, E. balteatus, and A. gifuensis will shrink, while those of other target insects will expand. Focusing on the scenario of high greenhouse gas emissions for the period of 2081–2100, all our target insects will move toward higher latitudes, and all of them will move toward higher altitudes except D. noxia. The niche overlap between three aphids (i.e., S. avenae, R. padi, and S. graminum) tends to increase with climate change in most regions. The aphid suppression capacity of ladybug H. axyridis will increase with climate change, while it will weaken for hoverfly E. balteatus and parasitoid A. gifuensis, showing that climate change can favor generalist over specialist enemies. We developed a new mathematical model for projecting wheat yield shifts due to climate change, and found a projected increase in net yield loss by aphids by the end of the century. Our results illustrate the food security imperative of clarifying the impact of climate change on cereal-producing systems, and provide insightful information for design of pest management strategies in the context of global climate change.