The influence of different modification methods on the surface properties of indium-tin-oxide (ITO) electrodes were investigated by measurements of chemical composition,surface roughness,sheet resistance,contact angle and surface free energy.Experimental results demonstrate that oxygen plasma treatment more effectively optimizes the surface properties of ITO electrodes compared with the other treatments.Furthermore,the polymer light-emitting electrochemical cells (PLECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized.It is found that oxygen plasma treatment on the ITO electrode enhances injection current,luminance and efficiency,thereby improves the device characteristics of the PLECs. The influence of different modification methods on the surface properties of indium-tin-oxide (ITO) electrodes were investigated by measurements of chemical composition, surface roughness, sheet resistance, contact angle and surface free energy. Experimental results demonstrate that oxygen plasma treatment more optimizes the surface properties of ITO electrodes compared with the other treatments. Fuerthermore, the polymer light-emitting electrochemical cells (PLECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized. It is found that oxygen plasma treatment on the ITO electrode enhances injection current, luminance and efficiency, thereby improves the device characteristics of the PLECs.