Two anodic electrochemiluminescence (ECL) pathways were resolved at Ru(bpy)^2^+~3/C2O^2^-~4 system on Pt electrodes, correspondign to two anodic potential resolved ECL peaks observed at 1.22V (vs. SCE) (peak 1) and 1.40V (peak 2), respectively. The location and intensity of these peaks were characterized by the different method of pretreatment of the Pt electrode, including polishing, pre- deoxidizing, pre-oxidizing sulfur modification, as well as the effect of C2O^2^-~4 concentration, medium pH, dissolved O2 and dissolved CO2. The mechanism of ECL peak 2 was proposed as the catalytic luminescence of CO^-^.~2 (or C2O^-^.~4) generated from direct electrode-oxidation of C2O^2^-~4.

Key words: ELECTROLUMINESCENCE, PLATIMUM ELECTRODE, CHEMILUMINESSENCE, RUTHENIUM COMPLEX, BIPYRIDINE P, OXALATO COMPLEX, CYCLOVOLTAMGRAPH