This paper mainly introduces the replacement construction of the old derrick of Guiping Qianjiang Bridge and the design and application of the special structure of the derrick. This project is to replace the old header wire of φ5 with an OVM.250 clip anchorage and GJ steel strand whole bundle extruding combined derrick. This scheme is the first time in the design of the two different anchoring methods combined, and used in the old bridge cable replacement. According to the particularity of the structure, the design idea and the special construction method of the derrick are introduced.