The invention discloses a splicing and welding method of a large converter five-connection-rod hanging device. The method includes the steps that a backing ring and a converter body are sequentially hung into a bracket on a steel ladle trolley through a workshop travelling crane; the converter body is pushed to a converter work position through the steel ladle trolley, after a relevant position is precisely adjusted, two sets of horizontal connection rods are preassembled first, positioned on and fixed to a support on the converter body; the converter body is moved downwards, the horizontal connection rods are welded to the support on the converter body, the converter body is moved upwards, and two sets of horizontal connection rod devices are reassembled; and the procedure of 'preassembly-disassembly-reset assembly' is adopted to complete splicing and welding work of three sets of vertical connection rod devices. The splicing and welding method of the large converter five-connection-rod hanging device can effectively solve the problems that when the large converter five-connection-rod hanging device is installed and welded, space is narrow, and the requirement for the matching precision of the connection rods and pin shafts is high.