Abstract: Through abundant geological investigation of in-situ construction tracing of the 700-meter-long slope of a large hydroelectric station in the southwest of China, the deformation response of high rock slope with large sloping ratio is studied under complex geological and high in-situ stress. Through systematical studies, the basic laws and special characteristics of its deformation responses are acquired and classified as follows: (1) During the slope excavation, the slope deformation and its excavation process exhibit strong synchronism. (2) The slope deformation is mainly influenced by the excavation. (3) The slope deformation generally decreases with the distance between the excavation face and the monitoring position, whose responding features of the ultimate stability have three stages, that is, rapid increase stage of deformation, slow enhancement stage and stable stage.