In this paper, we report a novel rare earth metal complex with the weak ligand of aromatic sulphonic acid (pyridine-3-sulfonic acid, 3-pSO(3)H), and characterized by FT-IR, UV-vis, energy-dispersive X-ray spectroscopy (EDX), electrochemiluminescence spectra, etc. Then an excellent electrochemiluminescence (ECL) signal was observed with K2S2O8 as the coreactant in NaAc-HAc buffer solution. For another thing, the electrochemical properties of the compound have been thoroughly investigated in acetonitrile solution, the possible ECL reaction mechanism was proposed as well. Furthermore, a simple and straightforward ECL platform was reported for sensitive and selective detection of Cd2+ due to the effective quenching after addition of Cd2+. Other heavy/transition metal ions do not interfere with the sensing. The limit of detection is determined as 0.13 nM, the results suggested that as-prepared complex could be a promising material for developing ECL senors to detect the Cd2+ rapidly indwell in environmental and practical samples. (C) 2017 Elsevier Ltd. All rights reserved.