Graphene has shown fascinating applications in bionanotechnology, including DNA sensing, protein assays, and drug delivery. However, exploration of graphene with intracellular monitoring and in situ molecular probing is still at an early stage. In this regard, we have designed an aptamer-carboxyfluorescein (FAM)/graphene oxide nanosheet (GO-nS) nanocomplex to investigate its ability for molecular probing in living cells. Results demonstrate that uptake of aptamer-FAM/GO-nS nanocomplex and cellular target monitoring were realized successfully. The dramatic delivery, protection, and sensing capabilities of GO-nS in living cells indicate that graphene oxide could be a robust candidate for many biological fields, such as DNA and protein analysis, gene and drug delivering, and intracellular tracking.