Abstract: Underground high-power electric heater is the core equipment of electric heating technology, and there is no production unit with mature manufacturing technology in China. Therefore, combining existing theories of tube and bar rolling with the production process of rigid cables, a continuous rolling process for underground high-power electric heater was proposed, and the metal strip coiling, powder filling and continuous rolling were combined into a production line. Then, through experiments and finite element methods, the key influencing factors such as diameter reduction deformation of outer sheath,rolling density of magnesium oxide powder filling, equivalent yield strength and interface bonding strength were studied to prepare a good electric heater. Its maximum rolling density of magnesium oxide powder was about 2.80 g·cm-3, and the equivalent yield strength was about 120 MPa. Furthermore, the continuous tube and the electric heater are effectively combined, and the mechanical bonding force reached 3.4 MPa.