Functionalized graphene oxide (GO) for the targeted intracellular delivery of hTERT siRNA was prepared by conjugating GO with polyethylene glycol (PEG) and folic acid, followed by the loading of siRNA with the aid of 1-pyrenemethylamine hydrochloride via π–π stacking. It was found that it could target the HeLa in vitro and the transfected hTERT siRNA could knockdown the protein expression level and mRNA level efficiently.