An approach was presented for the preparation of 3D nitrogen-doped graphene（3D rGO-DA） using dopamine（DA） as both reductant and functionalizing agents. Compared with reduced graphene oxide（rGO）,the 3D rGO-DA shows an excellent absorption ability toward Pb2+ and Cd2+.The adsorption capacities of 3D rGO-DA toward Pb2+ and Cd2+ were found to be 91.4mg/g and 43.5mg/g,respectively.The effect factors,including adsorption times, pH values and initial concentrations of Pb2+ and Cd2+,were studied. Adsorption time of 120min and pH 5.0 was found to be the suitable condition for Pb2+ and Cd2+ adsorption. The removal efficiency of Pb2+ and Cd2+ reached maximum value of 100% and 87.7% at the initial concentration lower than 30μg/mL, respectively. After 3 cycle absorption/desorption,the 3D rGO-DA still remained an excellent absorptive capacity,and could be easily removed from water with HCl after adsorption process, indicating its applicability in the water purification.