The present invention relates to a method for separating ammonia carbon in melamine tail gas. The method is characterized by comprising absorption, distillation, rectification, decarbonization and other steps. The method has the following advantages that: the low pressure steam produced by the triamine urine washing tower is utilized at a maximum, and the heat of the urine washing tower is recovered by adopting the forced circulation way so as to reduce the steam consumption during the separation process; and the separated water is adopted to replace the desalted water and is supplemented into the urine washing tower steam chest so as to be recycled, such that the apparatus achieves no wastewater discharge so as to provide characteristics of water saving and environment protecting.