The invention relates to a step swirling flow vertical shaft. The vertical shaft comprises a vortex chamber section and a vertical shaft section connected with the vortex chamber section, wherein the vortex chamber section is provided with a water inlet used for introducing the water stream of an approach channel in a vortex chamber tangentially; the vertical shaft section is a cylinder, the bottom end of the vertical shaft section is provided with a baffle well, the lower part of the vertical shaft is communicated with a flood discharge tunnel through a flip bucket and a pressing slope section; the wall of the vertical shaft is provided with a step energy dissipater; the first step of the step energy dissipater is provided with an air vent, the air vent is communicated with the top of the vortex chamber section through a vent pipe; and the bumps of the step sections of the step energy dissipater are arranged on the line connecting the starting point of the first step with the centre of the bottom of the vertical shaft to form a obconical flow passage, thus increasing the revolution of water stream, reducing the flow rate of water stream, increasing the pressure on the wall of theshaft and avoiding damages caused by cavitation.