A method for regenerating activated coke used for treating wastewater or sewage is provided. The method includes loading the activated coke to an environment under 150 to 250° C., heating the activated coke to a temperature of 700 to 850° C. for about 40 to 90 minutes; and providing a steam to the activated coke with a rate of 0.1 to 0.5 m3/(ton of activated coke). When the activated coke is being heated at the temperature, it generates a gas mixture including a steam portion and at least a paraffine gas. The gas mixture flows along a reverse direction relative to a flow of cooling water, so that the steam portion is converted into a part of the cooling water for recycling. The paraffine gas is used as a fuel. An apparatus for regenerating the activated coke used for treating wastewater or sewage is also provided.