The present study computationally investigates the steady incompressible flow behavior through Langston turbine cascade. A three dimensional numerical model was developed by ANSYS-Fluent software. The model solves the RANS governing equations along with the transition-SST (4eq.) model. The results of the model have been validated using experimental data obtained by Langston. A proposed configuration to improve the turbine performance is adopted using fence mounted close to the leading edge. The function of the fence is to reduce the pressure losses and accordingly improve the turbine performance. The results showed that the total pressure loss coefficient decreased by 5.244 % according to fence addition. The fence effectively disrupted the horseshoe vortex and modified the pressure flow field, leading to a weakened passage vortex and suppressed secondary flow. Adding a fence resulted in an enhancement of the flow uniformity and reduction of the vortex strength with improvements in the aerodynamic efficiency of the turbine cascade.