The invention relates to the technical field of wastewater treatment, and discloses a method for treating foam drainage gas recovery wastewater. The method includes the steps that 1, the foam drainagegas recovery wastewater is subjected to coagulating sedimentation treatment, so that supernate is obtained; 2, the supernate is oxidized to remove ammonia nitrogen in the wastewater; 3, the wastewater obtained in the second step is subjected to ion exchange treatment so as to remove a surface active agent in the wastewater and obtain ion exchange effluent; 4, the ion exchange effluent is subjected to evaporation treatment. In the method, operation conditions are neutral or approximate to be neutral (without strong acid conditions and strong base conditions), a technology is simple, costs arelow, and the application range is wide; after treatment, water can be purified substantially, and the problem is effectively solved that the foam drainage gas recovery wastewater is difficult to treat.