The dredger has a complicated underwater operation environment, poor industrial control and high cost. The accuracy of construction monitoring sensors and instruments is directly related to construction safety and production efficiency. In order to ensure the accuracy, stability and reliability of the dredging construction monitoring equipment of the construction vessel, we have prepared precision position verification devices, ship alignment verification devices, reamer depth calibration devices, pressure calibration devices, flow rate verification devices providing regular calibration work for key metering equipment without traceability and dredging construction.