Abstract: Rock anchor beamis mainly used in the installation and maintenanceofmechanicaland electrical equipment in the underground powerhouse of large water conservancy project.Compared with rock bench beam and other structural beam, it can narrow downthe span of underground powerhouse, reduce the work amount, reduce the project cost and increase the stability of cavern.It analyzes the Yunnan Lantsang RiverNuozhadu HydropowerStation underground powerhouserock anchorbeam excavation plan and discusses its construction method.