Abstract: An equipment for treating sewage, comprises a horizontal plate with a water sinking hole dividing the equipment into two portions: an upper portion of biofilter and a lower portion of contact oxidation pond. Within such equipment, a two-stage sewage biochemical treatment is accomplished. The equipment of the present invention has the advantages of less land occupation, less energy consumption, higher pollutant removing rate, higher shock resistance, easy management, no excess sewage and waste gas being drained off and less secondary pollution.