A high-load vertical ultradeep bioreactor comprises a reactor body and a head box. An aerating device, a water inlet pipe, an air supply pipe and a water outlet pipe are disposed in the reactor body, and an air inlet of the air supply pipe is connected with an air compressor. The high-load vertical ultradeep bioreactor is characterized in that a water outlet of the water inlet pipe is positioned in the axial middle of the reactor body, an air outlet of the air supply pipe is lower than the water outlet of the water inlet pipe, and a water inlet of the water outlet pipe is positioned at the inner bottom of the reactor body and below the aerating device. An inner tube is further arranged in the reactor body, an upper port of the inner tube is higher than the top end of the reactor body and positioned in the head box, and a bottom port of the inner tube is lower than the water outlet of the water supply pipe and higher than the air outlet of the air supply pipe. Water power short circuit is avoided during operation of the high-load vertical ultradeep bioreactor, and circulation of a whole system can be realized with less air flow. In addition, the high-load vertical ultradeep bioreactor has the advantages of simple structure, low cost, small occupied are, higher hydrogen utilizing rate, low operation and maintenance cost, less foam and the like, and is applicable to treatment of industrial wastewater and urban sewage.