The invention relates to a method for extracting and separating tungsten in an aqueous solution from an aqueous two-phase system. The method is characterized in that polyethylene glycol, a tungsten-containing aqueous solution, a saline solution, and deionized water are mixed and uniformly stirred, the mass fraction of a nonionic surfactant is 10-20%, the mass fraction of tungsten is 0.1-5%, and the mass fraction of salt is 6-12%; a pH value is adjusted to 2-3, the material is stirred for 10-60 min at the temperature of 30-60 DEG C, standing is carried out for phase splitting for 10-60 min, andthe aqueous two-phase system having an upper phase being a nonionic surfactant phase loaded with phase and a bottom phase being an aqueous-phase; the back extraction temperature is 40-70 DEG C, the stirring time is 20-60 min, and the phase separating time is 20-60 min, the phase ratio (A:O) of the nonionic surfactant phase loaded with phase to an ammonium carbonate aqueous solution is 1:1-4:1, and the back-extraction product is ammonium tungstate. The method has the advantages of fast extraction rate and good phase separating, tungsten single-stage extraction yield can achieve more than 98%,and the tungsten single-stage back-extraction yield can achieve more than 97%.