In this study, we have numerically investigated the hydraulic efficiency with various values of discharge angle($11^{circ}$, $12^{circ}$, $14^{circ}$, $15^{circ}$, $17^{circ}$, $18^{circ}$, $20^{circ}$) in the Francis turbine of hydropower generation under 15MW with fixed values of head range of 151m and flow rate($10.97m^3/s$). We also conducted the numerical analysis with constant inlet angle in the Francis turbine using the commercial code, ANSYS CFX. Hydraulic characteristics for different values of the runner blade angle are investigated. The results showed that the change of discharge angles significantly influenced on the performance of the turbine hydraulic efficiency.