A novel electrochemiluminescence (ECL) system that consists of the copper sulphide (CuS) film and K2S2O8 was prepared and used for detecting crystal violet in aqueous solutions. The CuS film was a luminescent semiconductor material, which was modified on glassy carbon electrode (GCE) via one-step electro-deposition. To enhance the ECL intensity, K2S2O8 was added into the solution. The morphology and composition of the modified electrodes were analyzed with scanning electron microscope, energy-dispersed spectrum, transmission electron microscope, high resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy. Electrochemical impedance spectroscopy (EIS) was studied for different electrodeposition time. Under the optimal conditions, the ECL intensity of the quenching value (Delta ECL) versus the logarithm of the concentration of crystal violet was linear over a concentration range from 5.0 x 10(-8) to 1.0 x 10(-5) mol L-1 (r = 0.9926) and the limit of detection (LOD) was up to 3.2 x 10(-9) mol L-1.