The utility model relates to an adopt electric heating element of boron nitride as insulating material, including the electrothermal tube outer tube, characterized by: the boron nitride powder is all filled including district and the cold junction of generating heat at generate heat district and cold junction to the inner chamber of electrothermal tube outer tube, it sets up the heating wire in the boron nitride powder in district to generate heat, sets up cold needle in the boron nitride powder of cold junction, the surface of electrothermal tube outer tube sets up the helical shape cooling surface. The one end of cold needle is connected with the heating wire, and the other end of cold needle is stretched out by the tip of cold junction. The cooling surface arch is in the surface of electrothermal tube outer tube, the transversal arc surface of personally submitting. Top distance of tube -surface outside the electrothermal tube of cooling surface is 1~2mm. The utility model discloses high pressure heater thermal element power density, application temperature, insulation level and dielectric strength can be carried greatly, electric heating element's heat exchange efficiency has been improved simultaneously.