The invention relates to the field of metallurgical aluminum preparation and discloses a method and a device for removing organic matters in aluminum oxide mother liquor with assistance of an aluminumash sintering process. The method is characterized by comprising the following steps: guiding raw material slurry into a rotary kiln through a raw material pipe; guiding natural gas and air into therotary kiln through a fuel pipe and an air pipe respectively for a sintering reaction; guiding clinker obtained by the sintering reaction into a cooling machine through a cooling pipe; finally, feeding the clinker cooled by the cooling machine into a ball mill through a conveyor; adding aluminum oxide evaporation mother liquor and sintering again to finish removal of organic matters in the aluminum oxide mother liquor; thus, inert aluminum ash in the aluminum ash can be safely and effectively treated, total recovery rate of aluminum in the aluminum ash reaches 95% or more, overall recovery rate of organic matters is 85% or more, and the problems of high consumption and cost of additives, difficulty in operation and implementation, difficulty in regeneration and low recovery efficiency of existing methods such as crystallization, oxidation, roasting, ion exchange and causticization for removing organic matters in aluminum oxide are solved.