The performance of herbivores is directly determined by the quality of host plants which changed rapidly with abiotic environment. Elevated CO2-induced nitrogen decreases in plant foliage reduces the growth of chewing herbivorous insects. In contract, although aphids had species-specific response to elevated CO2, it was still considered that aphids’ population have been found to be the only feeding guild to respond positively to elevated CO2. Few studies of elevated CO2 effects on sap-feeding aphids can explain why aphids would make its success under elevated CO2 environment. Plant re-allocates the carbon and nitrogen in tissue under elevated CO2, and in turn alters structure of plant leaves, reduces the amino acid content of phloem sap and increased secondary metabolites of plant. However, it is difficult and unreasonable to predict the general response of aphids to elevated CO2 by using a single plant component. Instead, it is more likely that, in terms of interacting with host plant, aphids are trying to overcome the disadvantages of elevated CO2 and maximum their fitness under elevated CO2 environment. It may provide several cues to explain why individual species will achieve success under future elevated CO2. The present paper reviews recent studies of elevated CO2 effects on aphids and discusses the effects of elevated CO2 on aphid performance on crops using cotton and cereal aphids as examples. Further work examining induced defense of plant against aphids under elevated CO2 will contribute largely to current knowledge.