Abstract: The problems existing in rock mass in-situ test, in present selection of deformation parameter, and in conventional compution model are analyzed. Based on the weathering, wave velocity and ground stress of rock masses having their progressive changes from superficial to deep part, a selection of the proggressively changing rock mass deformation parameter is presented. The displacement values monitored during the time of initial impoundment of the reservoir of Lijiaxia Hydropower Station in the upstream of Yellow River prove the reasonableness of the selection of progressively changing rock mass deformation parameters in space. The result is of realistic guiding significance for selection of mechanical parameters and the generalization of compution model in other rock mass engineering projects in the future.