The invention relates to a rotary joint and belongs to the technical field of heat power pipe network matching. The joint comprises an outer pipe, an inner pipe and a gland, wherein an inner convex ring is arranged inside the outer pipe, an outer convex ring is arranged outside the inner pipe, the inner convex ring and the outer convex ring are respectively provided with V-shaped grooves of which openings are opposite, and obliquely-arranged cylindrical rollers are mounted inside the V-shaped grooves; one end of the inner convex ring adopts an expanding section with an annular space, and a C-shaped elastic metal sealing ring is embedded into the annular space; a trapezoidal baffle ring with an inclined plane at one end is mounted at the other end of the inner convex ring, the inner end of the gland adopts an inclined plane which is opposite to the inclining direction of the trapezoidal baffle ring, and a graphite filling material sealing ring is mounted between the trapezoidal baffle ring and the gland. After the adoption of the invention, the C-shaped elastic metal sealing ring and the graphite filling material sealing ring form high-temperature resistant and high-voltage resistant double sealing, the arranged direction of a bearing and the trapezoidal cross section graphite filling material sealing ring form a reasonable force bearing system. Therefore, the rotary joint provided by the invention has remarkable advantages that reliable sealing under high-temperature and high-voltage conditions is kept while free rotation can be ensured.