Abstract: The geological structure of the slope at the right-bank of Longtan hydropower stationis very complex. It has a large district which was deeply air-slaked and eroded rock-earth.damage case or potential harm situation have occurred many times and a huge volume of slope slide took place during the course of construction. The cases were under being monitored and predicted to prevent or minimize loss in order to ensure construction activity safety. Now the slope condition trends to be stable according to the analysis of monitoring results after it was improved strength by anchorage cables and piles.