The invention discloses a sealing flange used for a high-temperature oil pump of a heat conduction oil furnace. Two flange pieces are welded to the two ends of a pipe body. Multiple air cylinders are arranged on the outer wall of the pipe body. Two pistons are arranged at the two ends of each air cylinder, wherein an airtight space is formed between the two pistons, and a spring is connected between the two pistons. An annular groove is formed in the connecting face of the flange pieces, a magnetic metal gasket is arranged in the annular groove, multiple through holes are formed in the annular groove, and the top ends of the pistons penetrate the through holes to abut against magnetic metal gasket. By means of the sealing flange used for the high-temperature oil pump of the heat conduction oil furnace, high-temperature heat conduction oil in a pipeline is used for heating nitrogen in the air cylinders, the nitrogen is heated to expand to push the pistons to press the magnetic metal gasket, the magnetic metal gasket acts on a sealing flange gasket so as to compensate for the clearance generated due to heating expansion, and the overall sealing performance of the flange is greatly improved.