The invention relates to an overline operation crane for high-speed railways, belongs to the field of cranes and particularly relates to high-speed railway and rail transit cranes. Two transversing mechanisms including a front transversing mechanism and a back transversing mechanism are respectively erected on four supporting trolleys of a double-line rail, and are in butt joint with the crane through auxiliary supporting legs, and the crane is separated from the original rail line under action of auxiliary supporting leg jacking cylinders, and transverses to the middle of the double-line rail. The front transversing mechanism and the back transversing mechanism moves to be close to the center of the crane together with the front and back corresponding supporting trolleys by retracting effect of the auxiliary supporting legs. Until the auxiliary supporting legs are retracted completely, four crane supporting legs of the crane are unfolded, ball hinges at the tail ends of cylinders of the four crane supporting legs are disposed in ball hinge seats of longitudinal beams of the four supporting trolleys on the double-line rail, and then acting force of the crane to a single-line rail is distributed to the double-line rail successfully, so that operations including overline craning and the like can be carried out for the high-speed railways, and requirements for large-tonnage cranes during rescue and construction on bridge sections of the high-speed railways are met.