Background Chitosan nanoparticles (CTS-NPs) protect the active ingredients from the environment for a specific period and reduces sweating, control weight loss, delay ripening, and increase vase life. So, a factorial experiment was carried out as a randomized complete design in three replications to investigate the efficiency of CTS-NPs in quality improvement and longevity extension of cut rose flowers. Results The 15-day maximum vase life was attained by the rose placed in a preservative solution containing 10 mg L− 1 CTS-NPs. CTS-NPs also reduced microbial growth as compared to controls. Total phenolics, total flavonoids, and amount of anthocyanin in treated petals were dramatically increased. CTS-NPs solutions especially at 10 and 15 mg L− 1 concentrations, markedly reduced the H2O2 and malondialdehyde at the end of 15th day and maintained the membrane index. The protein and carbohydrate and petals anthocyanin content and enzymatic activities such as superoxide dismutase, polyphenol oxidase, peroxidase, catalase and ascorbate peroxidase increased in cut roses placed in 10 mg L− 1 CTS-NPs vase solution which in turn caused to increase in vase life. Conclusion CTS-NPs especially at a level of 10 mg L− 1 can assist plants to enhance light usage efficiency, as well as promote photosynthetic carbon fixation and the production of additional carbohydrate products for plant growth and development.