Global atmospheric CO₂ concentration which has been increasing at an accelerating rate attracted widespread attention. Most of studies were focused on the response of plant to elevated CO₂, but little was known about whether elevated CO₂ can change the performance of herbivorous insects. [Methods]  In this experiment, the effects of elevated CO₂ were evaluated on the transcriptome changes of green peach aphid Myzus persicae fed on two Arabidopsis genotypes, a npr1 mutant (deficient in salicylic acid signaling pathway) and wild-type control (wt) by using high-throughput screening technology. [Results]  The study showed that the increase of atmospheric CO₂ concentration only promoted the weight of green peach aphid fed on npr1 mutant but had little effect on aphid fed on wild type plants. In addition, the weight of aphids fed on npr1 genotype were significantly lower than those of the wild type under ambient CO₂. Furthermore, we used pathway enrichment analysis to identify metabolic pathways or signal transduction pathways that were significantly enriched in DEGs (Differential Expressed Gene) relative to the whole transcriptome background of green peach aphid associated with different treatments. Among all the genes，220, 274, 661 and 536 genes were significantly enriched in DEGs when aphids responded to elevated CO₂ fed on wt plants, elevated CO₂ fed on npr1 plants, plant genotypes under ambient CO₂, plant genotypes under elevated CO₂, respectively. Among all the genes subjected to KEGG pathway annotation and enrichment analysis, 9, 16, 12 and 15 pathways were significantly enriched in DEGs when aphids responded to elevated CO₂ fed on wt plants, elevated CO₂ fed on npr1 plants, plant genotypes under ambient CO₂, plant genotypes under elevated CO₂, respectively. The common pathways significantly enriched in DEGs when aphids responded to plant genotypes under ambient CO₂ and elevated CO₂ fed on npr1 plants: protein processing in endoplasmic reticulum, proteasome, pyruvate metabolism and antigen processing and presentation. [Conclusion]  The effects of elevated CO₂ on aphid weight exhibit host plant genotype-specific. The enhancement of elevated CO₂ on the body weight of aphids associated with npr1 mainly due to the increase of aphid primary metabolism including amino acid metabolism, fatty acid metabolism as well as carbohydrate metabolism.