Hydraulic characteristics of rock plug blasting are the key to successful construction of rock plug inlet/outlet. In this paper, the hydraulic characteristics of rock plug blasting at the inlet/outlet of the lower reservoir of a pumped storage power station are studied by means of physical model test. The characteristic laws of water hammer pressure, surge of gate shaft and accumulation effect during blasting are obtained. The results verify the rationality of the design type of rock plug inlet, and demonstrate the feasibility of using gate direct water blocking scheme and high water level blasting during rock plug blasting. The research results can provide technical support for the design and construction of this project, and provide reference for similar projects.