The invention relates to a welding technology of super-high-strength high-toughness X120-level pipeline steel circumferential welds. The technology includes the following steps that (1), parent metal is prepared; (2), welding wires are prepared; (3), edge milling is performed; (4), rust and oil are removed; (5), protecting gas is adjusted; (6), pairing is performed; (7), a welding machine is started; (8), point fixing is performed; (9), preheating is performed; (10), root welding is performed; (11), slag crust and splash are eliminated; (12), interlayer temperature is controlled; (13), thermal welding is performed; (14), slag crust and splash are eliminated; (15), interlayer temperature is controlled; (16) the first time of filling welding is performed; (17) slag crust and splash are eliminated; (18), interlayer temperature is controlled; (19) the second time of filling welding is performed; (20) slag crust and splash are eliminated; (21), interlayer temperature is controlled; (22), cosmetic welding is performed; and (23) slag crust and splash are eliminated. By means of the welding technology of the super-high-strength high-toughness X120-level pipeline steel circumferential welds, it is guaranteed that the welding quality meets the using performance requirement, and meanwhile grain coarsening of a welding heat effect region and softening of a welding connector are obviously improved; the using quantity of welding materials can be reduced easily, the welding efficiency is improved, and the welding and manufacturing cost is reduced; and the beneficial effects that movability is good and adaptability is wide are achieved, and the welding technology can adapt to various complicated field construction conditions.