The invention discloses a device and a method for treating wastewater containing nitrobenzene, aniline and cyclohexylamine. The device comprises a water collection pool, an acid regulation pool, a catalytic oxidation pool, a PH neutralization pool, a sedimentation pool, a hydrolytic acidification pool, a primary anaerobic pool, a secondary anaerobic pool, a UASB (upflow anaerobic sludge blanket) pool, a contact oxidation pool, a primary aerobic pool, a secondary aerobic pool, a SBR (sequencing batch reactor) pool and a buffering pool. Multi-chain benzene ring substances in waste water are subjected to chain scission in the catalytic oxidation to obtain single-chain substances, a flocculating agent is added after the PH value is regulated through the neutralization pool, flocculated wastewater is subjected to slurry-water separation in the sedimentation pool, complex organic matters in an anaerobic system are decomposed into simple dissolved organic matters under the action of extracellular enzymes generated by zymogeneous bacteria, increase of a B/C ratio and improvement of wastewater biodegradability can be realized under the hydrolysis action of the hydrolytic acidification pool, residual pollutants in the wastewater are thoroughly degraded after treatment in the SBR pool, and after decolorization in an activated carbon adsorption tank, the treated wastewater can be discharged on standard.