The embodiment of the invention discloses a trenchless pipeline repairing device, which comprises a barrel-shaped sealing ring and two end part support rings positioned in an inner cavity of the barrel-shaped sealing ring, wherein the two end part support rings are supported at two sealing ends of the barrel-shaped sealing ring respectively; the end part support rings are circular rings of which the shapes are adaptive to the inner wall of a pipeline, and are provided with notches; two parallel adjusting sheets are arranged at each notch; the adjusting sheets are positioned on the inner sides of the end part support rings, and are provided with threaded holes. The trenchless pipeline repairing device further comprises threaded rods, wherein the thread directions of threaded parts at two ends of each threaded rod are opposite, and the threaded parts are matched with the threaded holes at the same ends respectively. According to the trenchless pipeline repairing device, the problem that a radial dimension can only be unidirectionally adjusted, which exists in a trenchless repairing sleeve adopting a mode that a buckle slides in a gap of a unidirectional tooth structure to adjust the radial dimension of a sleeve in a background technology can be solved. The invention further discloses a trenchless pipeline repairing method.