In this paper, it is studied the electrostatic discharge in insulating oil for the purpose of the technical control of the streaming electrification resulted frown the interface between an insulating liquid and a solid. The streaming current increases exponentially with flow rate and in region of lower than 50[℃] but decreases at higher than the same temperature. The phenomena of electrostatic discharge appear at an interface between measuring tank and insulating oil when the seven sheets of gauzos are inserted in electrification apparatus. And those of partial or surface discharge are shown when eight sheets are inserted.