Abstract: Aiming at the problems of the risk of personal injury and the risk of replacement failure caused by manual replacement, this paper develops a special tool for replacing the resin in the water cooling system of the converter station based on the principle of negative pressure jet, whose main structure consists of a jet, a resin storage, a control cabinet, a pump, a pump storage, and a resin recovery storage, etc. With this tool, personnel do not need to directly contact the resin and work at height, which can greatly reduce the risk of personal injury and reduce the loss of spillage during the resin replacement process. Thanks to the production of this tool, personnel do not need to directly contact the resin and work at height, which can greatly reduce the risk of personal injury, and at the same time reduce the resin in the replacement process of the spillage loss. Based on the annual maintenance field test of the regulator of a certain converter station, the effectiveness test of the tool was completed by carrying out the performance evaluation from the three dimensions of work efficiency, personnel safety and material safety, realising the improvement of the quality and efficiency of the resin replacement of the regulator, and filling the gaps of the special resin replacement tool in the market.