The graphene quantum dots (GQDs) were synthesized by a convenient method and immobilized to glassy carbon electrode (GCE) through covalent self-assembled method. The GQDs and the obtained (GQDs–NHCH₂CH₂NH)/GCE were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and atomic force microscopy (AFM), etc. Its electrochemical property of the (GQDs–NHCH₂CH₂NH)/GCE was explored carefully by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was demonstrated that the modified electrode presents good electrical conductivity and has favorable electrochemical response to dopamine (DA). The (GQDs–NHCH₂CH₂NH)/GCE displays a linear range from 1 to 150 μM and a detection limit of 0.115 μM (S/N = 3) to DA, which illustrates that the modified electrode is highly sensitive towards the determination of DA. The (GQDs–NHCH₂CH₂NH)/GCE also possesses good anti-interference capability and well stability. Furthermore, the sensor displays satisfactory results in real samples determination which demonstrate its great potential in practical applications