Surrounding rock stability and lining structure stress in acute angle region of reinforced concrete bifurcation is complex. Based on the practice of a certain pumped-storage power station, three-dimensional numerical model of the diversion bifurcation is proposed and the acute angle of bifurcation is optimized. By using finite element method (FEM) comparative analysis of stress and deformation of lining structure as well as the surrounding rock stability before and after optimization of different round radius have been performed. Numerical results show that after optimization, the range of plastic zone increases during construction period and the plastic concentration of surrounding rock slows down while the deformation of surrounding rock increases slightly because span at bifurcation point increases. The stress concentration of bifurcation and rebar reduce during operation period, thus the stress distributes more uniform. The bifurcation lining mainly endures compressive stress during overhaul period and the degree of local compressive stress concentration reduces with proper optimization, which has little effect on deformation. Thus, if surrounding rock is stable, one should reduce excavation and choose proper round radius, which is conducive to surrounding rock stability and lining structure stress.