An electrochemiluminescence (ECL) system based on cadmium sulfide quantum dots (CdS QDs) amplified the ECL of nitrogen and sulfur co-doped graphene quantum dots (N,S:GQDs) was established and applied for lead ion (Pb2+) determination. The anodic ECL signal of N,S: GQDs was enhanced greatly by CdS QDs; furthermore, the enhanced ECL signal could be quenched by Pb2+. Based on the quenching effect, a simple method for the selective ECL determination of Pb2+ was proposed.