The runner is a wheel that is located in the reaction water turbine and receives water energy to rotate. The runner consists of a blade, a crown, and a band, and the blade is welded to the crown or band. In this study, we propose a method of evaluating the residual stress that occurs when a blade inside a turbine runner is welded to a crown or band. The volume of the bead was modeled by estimating the bead accumulation with time, and the heat transfer analysis was performed with respect to the welding process. The structural analysis was performed using the temperature of the heat transfer analysis as the structure temperature. Finally, the residual stress generated in the structure during welding was confirmed and evaluated.