Tool suitable for double-cable synchronous tensioning of string structure and use method

The invention discloses a tool suitable for double-cable synchronous tensioning of a string structure. The tool comprises a force bearing frame connected with two symmetrically-arranged tensioning steel strands, and the tail ends of the two tensioning steel strands are connected with a first reaction frame and a second reaction frame respectively; a steel structure main beam is fixed between the first reaction frame and the second reaction frame and connected with the force bearing frame through double inhaul cables. The invention further discloses a use method of the tool. The method comprises the following steps that 1, according to the required linear types of the double inhaul cables and the required positions of anchoring nodes of the double inhaul cables in the design, the positionsof the first reaction frame, the second reaction frame and a pin shaft are determined; 2, according to the breaking load of the double inhaul cables and the size of an anchoring tool, the sizes of theforce bearing frame, the