The invention discloses an apparatus utilizing electrochemical reactions and photocatalytic reactions to process wastewater. The apparatus comprises an electrochemical catalytic device and a photocatalytic device. The electrochemical catalytic device comprises an electrochemical catalytic unit. The electrochemical catalytic unit comprises a first reaction cavity. Two anode plates are arranged in the first reaction cavity, and one cathode plate is arranged between two anode plates. The anode plates and the cathode plate are all connected to a power supply. The upper part of the first reaction cavity is provided with a first water inlet pipe, and the lower part is provided with a first water outlet pipe. The photocatalytic device comprises a second reaction cavity. The upper end of the second reaction cavity is provided with a second water outlet pipe. The lower end of the second reaction cavity is provided with a second water inlet pipe, which is communicated with the first water outlet pipe. A sleeve pipe is arranged in the second reaction cavity. The surface of the sleeve pipe is covered by a photocatalyst film. A UV source is arranged in the sleeve pipe. The provided apparatus can solve the problem that the energy utilization rate is low when wastewater is processed by a photocatalytic method and an electrochemical method individually, and is capable of processing organic wastewater effectively.