The invention discloses a tidal flow impeller generating set comprising a generator, a wheel hub directly connected with the shaft of the generator and a blade arranged on the wheel hub, wherein the cross section midline of the blade is in a double-curvature antisymmetric twist type; the cross section midline of the blade is an antisymmetric structure about the point of tangency of the cross section midline; the cross section thickness of the blade is gradually reduced from the middle to both ends; and both ends are thinnest and are rounded. The impeller of the generating set has a function of bidirectional running, and therefore, when the flow direction of the tidal flow is changed in rising or falling tide, electricity can be generated to supply electric energy without regulating the mounting direction of the impeller and carrying out blade rotation. The tidal flow impeller generating set does not consume energy sources when in use, does not have pollution and has simple structure.