The invention relates to a method for treating heavy emulsified oil in wastewater. The method is characterized in that a treatment device is formed by a lower bubble section and an upper foam section, wherein the lower bubble section of the treatment device is an airlift inner-circulation reactor, and the upper foam section of the treatment device is an overflow box type gas-liquid separator; thepH value of the wastewater is regulated to 8-9, and the wastewater is introduced into the bubble section; air is introduced to a tower bottom, and flocculating agents and a surface active agent are added, wherein the amount of an inorganic flocculating agent is 0.02-0.1mmol/g COD (chemical oxygen demand), the amount of a polymer flocculating agent is 10-50mg/m<3> wastewater, and the amount of an anion surface active agent is 5-20mg/g COD and is not less than 15-20mg/m<3> wastewater; the emulsified oil is separated from the wastewater through collecting foam; the gas speed of an empty tower ismaintained at 0.5-1.5cm/s; the separation efficiency is high: the primary separation rate can reach above 90%; the process is simple: solid suspended matters in the wastewater are removed once; the energy consumption and the reagent consumption are low: the amount of the flocculating agents is low; and the process flow is short.