Gold electrode (GE) is modified with composite of Au nanoparticles (AuNPs) and graphene quantum dots (GQDs), and its electro-chemical performance is evaluated. The modified electrode (GE/AuNPs/GQDs) exhibits higher electrochemical activity and better stability than bare GE and AuNPs or GQDs modified GEs. The higher electrochemical activity of GE/AuNPs/GQDs is attributed to the increase of the active surface area and the decrease of the interface transfer resistance that accelerates reactant absorption and electron transfer of the electrodes. In addition, pi-pi interaction between GQDs in the GE/AuNPs/GQDs and aromatic rings of phenolic compounds contributes to the enhanced electrochemical activity in detection of phenolic compounds. Given the high electrochemical activity and long cycling stability, the method for GE modification can be applicable to the detection of phenolic compounds. (C) 2019 The Electrochemical Society.