A three-dimensional numerical model of the underground powerhouse of the Shuibuya project was firstly established based on the results of geological investigation. Then

the detailed construction processes

including the replacement of soft rock

excavation as well as support

were numerically simulated. The distribution and evolution of stresses and displacements around the underground powerhouse with and without support system are compared and discussed. The further analyses demonstrate that the results from the numerical simulation agree fairly well with the in situ monitoring data; and the underground powerhouse with the designed support system is globally stable. This paper provides some significant results for the dynamic design optimization of the construction and support scheme of the underground powerhouse of the Shuibuya project.