The invention relates to an oxygen cathode electrolysis bath for electrolyzing high-concentration organic wastewater. The electrolysis bath comprises more than one electrolysis unit, wherein each electrolysis unit comprises an electrolysis chamber; an oxygen chamber is respectively arranged below each electrolysis chamber; the bottom of each electrolysis chamber is provided with an electrode prepared from a metal mesh in the horizontal direction; the electrode is electrically connected with an anode electric connecting plate; the edge of each electrode is respectively fixed to the bottom of the corresponding electrolysis chamber; at least one ultraviolet lamp tube is respectively arranged in each electrolysis chamber; one end of each electrolysis chamber is provided with a wastewater inlet, and the other end of each electrolysis chamber is provided with a wastewater outlet; the top of the side wall of each oxygen chamber is respectively attached to and connected with the bottom of the side wall of one electrolysis chamber; and the top of each oxygen chamber is respectively provided with a planar oxygen cathode in the horizontal direction. The oxygen cathode electrolysis bath for electrolyzing high-concentration organic wastewater has the advantages of high electrolysis efficiency, low energy consumption and high treatment speed, and can treat abundant wastewater.