The invention discloses a device and method for photo-catalytically degrading phenol-containing wastewater, and belongs to the technical field of industrial wastewater treatment. The device comprises a rotary disc reactor and a liquid storage tank, wherein the rotary disc reactor comprises a shell, a rotary disc, a rotary shaft, excitation light sources, a liquid inlet tube and a liquid outlet tube, wherein the rotary disc is horizontally arranged in the center of the shell, the excitation light sources are respectively arranged above and below the rotary disc, the rotary disc is driven to rotate through the rotary shaft, and the rotary shaft is controlled by a motor and a frequency converter. The rotary disc reactor and the liquid storage tank form a circulating system. The photo-catalytically degrading method comprises the following steps: (1) preparing a loaded photocatalyst; and (2) photo-catalytically degrading organic wastewater. According to the device and method disclosed by the invention, catalysts are simultaneously loaded on the inner walls of the rotary disc and the shell of the reactor, and the excitation light sources are installed above and below the rotary disc, so that the photocatalytic reaction time is prolonged, the mass transferring effect is intensified, and the efficiency of light energy utilization is improved. According to the device and method disclosed by the invention, the defects that the catalyst is hard to separate, low in efficiency of light energy utilization, complex in structure of photocatalytic reactor, difficult to apply industrially and the like in an existing photocatalysis technology are overcome.