In order to describe electrochemical behaviors of thiourea and provide fundamental for gold ore leached by alkaline thiourea system,the decomposed potential of thiourea oxidized in alkaline medium and the relationship between decomposition and concentration of thiourea were studied in detail by the methods of electrochemical techniques,such as stable polarization and cyclic voltammetry.The results indicate that the decomposition of thiourea is irreversible,and the corresponding decomposition potential is 0.5 V.With the addition of thiourea concentration from 0.05 mol/L up to 0.15 mol/L,the decomposition of thiourea is accelerated,the peak current increases from 1.559×10?4 A up to 9.068×10?4 A and the peak potential moves from 0.505 V down to 0.430 V.The decomposition of thiourea becomes serious with increasing pH value of system.