The utility model relates to a one time insulating frame for a high-voltage coil which is used for a high-voltage mutual-inductor. The utility model adopts resin insulating material, and the whole body is shaped by a mould vacuum injection. The utility model is composed of a barrel body, an upper end ring, a lower end ring and a middle spacing ring whose intersection has no seam, and the surface of the insulating frame body is not provided with sharp corners. The utility model has the advantages of large insulating resistance, large electric strength, large mechanical strength, no absorption of moisture, high temperature resistance performance, corrosion resistance performance, ageing resistance performance and crushing resistance performance. The utility model can be applied to manufacture a 35 kV high-voltage mutual-inductor, the degree of precision can reach a 0.2 stage, and the power frequency compressive strength can reach more than 105 kV per minute. The induction compressive strength is three times of the rated voltage, and lightning impulse is 250 kV chopped impulse.