In order to effectively recover small hydraulic energy, the influence of the blade design angle on the performance of the undershot water wheel has been estimated experimentally by the performance test of a mockup water wheel. The blades with chamber angle make the effect of the spread the operation point of the water wheel; however, the output of the pitch-flap blades with positive/negative large setting angle decreased due to the resistance by weight of the water in bucket and the buoyancy made by bucket. When the pitch angle is designed to be negative large, since the angle made by the momentum acting on the blades and the momentum contributing to the rotational force of the impeller increases, the mainstream momentum did not effectively convert to the impeller turning force.