The invention discloses a monitoring device for a big displacement telescoping device for bridge usage, comprising a plurality of sensors, a data collection unit, an intelligent control unit, a data transmission unit, a data processing unit and a client terminal. The data collection unit is connected to the sensor; the intelligent control unit is connected to the data collection unit through the data line; the data processing unit comprises a FPGA system, a signal emission module and a signal reception module; the FPGA system exchanges data with the intelligent control unit through the data transmission unit; the signal emission module transmits signal to the client terminal through the wireless network; and the signal reception module receives the signal of the client terminal through the wireless network. The function units of the system adopt he modularized design and is simple in structure. The invention collects the working state information of the telescopic device through the sensor, transmits the information through the network, and provides the data support to maintaining plane of the management department.