A remote monitoring system based on CAN-bus and database is developed to improve the on-line detection condition of the piston pin.The system can accomplish the integrated management of the excircle diameter measuring and data processing of the piston pin and utilizes eddy current transducer（ECT）as main measure device

STC89C58 microcontroller unit（MCU）and CAN-bus interface device as data acquisition board.The database and graphical user interface（GUI）are developed by programming Delphi procedure to achieve the storage and real-time display of the measuring data and results.The experiment result proves that the system runs stably and its measuring data is precise.