The invention discloses a separating method of a tetrahydrofuran-ethyl alcohol-water-methylbenzene mixed solution. The separating method comprises the steps of adopting a first extraction azeotropy lower side withdrawal rectifying tower and a second extraction azeotropy lower side withdrawal rectifying tower which are connected serially and have the same structures, wherein each structure comprises an upper-part extraction azeotropy section and a lower-part rectifying section; adding the raw material tetrahydrofuran-ethyl alcohol-water-methylbenzene mixed solution in the tower from the middle lower part of the extraction azeotropy section of the first extraction azeotropy lower side withdrawal rectifying tower, adding a composite extracting agent in the tower from the middle upper part of the extraction azeotropy section, obtaining tetrahydrofuran on the top part of the extraction azeotropy section, side withdrawing a mixed solution containing methylbenzene from the upper end of the rectifying section, and circulating the composite extracting agent on the bottom part to the extraction azeotropy section for recycling; carrying out the same treatment on the mixed solution containing the methylbenzene in the second extraction azeotropy lower side withdrawal rectifying tower. Compared with a traditional process, according to the method provided by the invention, a separating effect can be effectively improved, a technical process is simplified, and the energy consumption required by separation is remarkably reduced.