An oil-pressure swaging tool for rebuilding a connecting pipe includes an abutting member abutting against an oil-pressure device, a connector inserted into a connecting pipe, one end of a first axial member passing through the abutting member to connect to one end of the connector, another end of the first axial member connected to the oil-pressure device, a rebuilding member assembled to another end of the connecting pipe, a pressure collar adjacent to one end of the rebuilding member, one end of a second axial member passing through the rebuilding member to connected to the pressure collar, another end of the second axial member connected to another end of the connector. Therefore, when the opening of the connecting pipe is rebuilt by the oil-pressure swaging tool of the present invention, one end of the connecting pipe is not necessary to abut against a wall because of the abutting member.