This paper summarizes the main diseases of D160 and above modular telescopic devices in bridges,including rubber strip damage,steel structure corrosion,displacement box problems,bearing sliding or falling off,displacement control spring aging,abnormal joint width,abnormal noise,etc.,and analyzes the causes.The paper also puts forward the daily inspection methods and abnormal condition disposal procedures,emphasizes the importance of expansion devices,and advocates fine maintenance to improve the level of bridge maintenance.