Abstract: It has been fully evaluated for the monitoring equipment in Chencun hydropower plant and the modification has been carried out before the foundation of dam safety automation system. The I stage modification was performed in 1998, under the carefulness of the maintenance and management by stuff, this system has been operating successfully for 5 years. The system not only reduce the work intension, but also pick up the valued monitoring data which cannot be fulfilled by artificial method. It provides a technical basis for analysis on dam operation condition.