The hydrogeology is an important factor affecting the stability of slope.In order to provide a sufficient basis of science for the study on slope stability, a detailed survey of climate, distribution of annual rainwater, rainfall, torrential flood, waterlogging on ground, and latent water in weathering fissures etc. in the region where the west slope of Huidong opencast lies has been made, including the aquifers, inflow locations and water inflow in the mine area. This doing can make us work out more practical and effective preventive measures to control pit slope.