The invention relates to the technical field of production of rubber antioxidant midbody, and particularly discloses a separation method of a hydrogenated mixture in the production process of p-aminodiphenylamine. The separation method is characterized in that hydrogenated mixed liquid is sent to a desolventizer tower to remove hydrogenation reaction solvent alcohol, and the rest mixed liquid is recovered from the tower bottom; the tower bottom mixed liquid is sent to an extraction separating tower, meanwhile an extraction solvent is melted in the tower, aniline and p-aminodiphenylamine in themixed liquid are extracted out to serve as an oil phase to be extracted from the tower top of the extraction tower, and a tetramethyl ammonium hydroxide water solution is extracted from the tower bottom; and the oil phase is sent to a distillation separation procedure, an extraction agent and aniline are steamed from the tower top respectively, and p-aminodiphenylamine is extracted out from the tower bottom. Compared with a traditional separation method, the separation method effectively improves the layering speed and the separation effect of the oil phase and a water phase, water consumption amount is small, the postprocessing difficult for recycling a condensation catalyst-tetramethyl ammonium hydroxide is reduced, consumption of the condensation catalyst is decreased, meanwhile the extraction agent is easy to recycle for cycle use, and the method is convenient and rapid, and economical and effective.