The expansion joint of railway concrete bridge is an important part of the overall waterproofing of the bridge deck, which is directly related to the effectiveness of the bridge waterproof system and the durability of the structure. High-speed railway concrete bridges generally use rubber water-stopping expansion joints. Due to the difficulty in construction of rubber waterstops, it is easy to cause the rubber strips to be not firmly embedded, or because the installation precision is not well controlled, it is easy to cause misalignment and twisting. The deformation of the expansion joint seriously affects the quality of the anti-drainage of the expansion joint. When the expansion joint strip falls off and the function is lost, it is very difficult to replace. In recent years, domestic railways have gradually begun to use polyurethane elastomer elastomer sealing materials instead of conventional rubber waterstop expansion joints. However, the conventional liner method is complicated in construction, low in work efficiency and low in quality assurance rate. The construction method of the elastomer casting is a very meaningful thing.