Abstract: In order to investigate the flow electrification characteristics of oil-paper insulation under the AC superimposed DC electric field, an oil-paper tube model with concentric cylindrical electrode geometry was built in laboratory. Experiment study on flow electrification under AC superimposed DC electric field was carried out with the closed oil circulating system, and the influence of voltage amplitude, DC component ratio and oil flow velocity on flow electrification was discussed. The experiment results show that the influences of oil flow velocity and the amplitude of applied voltage on streaming currents are related to temperature. At low temperature, the streaming current increases linearly with flow velocity and amplitude of applied voltage, and the increase of the DC component ratio can enhance the streaming current. At high temperature, the streaming current increases exponentially with flow velocity and shows peak effect with amplitude of applied voltage. The peak point voltage decreases with the DC component ratio. The theoretical analysis demonstrates that the streaming current depends on migration and diffusion rate of the negative ion in paper at low temperature. However, at high temperature, it is related to the stripped rate of positive ion by oil flow and the charge leakage rate at the outer electrode. The temperature can influence the flow electrification characteristics by affecting the ions migration speed and the electric field distribution in the insulation.