By using three-dimensional analysis method of FEM, the numerical simulation was conducted for the lining and surrounding rock of the surge thaft of Bulunkou - Konggur hydropower station. It evaluated the stability of the surge shaft in running stage and proposed specific recommendations to improve the stability of the supporting structure through the analysis of the lining and surrounding rock of the surge shaft stress and deformation. The result can provide a reference for the design of throttled surge shaft with long and narrow upper chamber of similar projects.