The removal effect of nitrobenzene (NB) in water by VUV/O3/GAC synergetic catalyzing method in a nebulizing system was studied. In addition, the effects of the droplet size, the nebulization height, O3 flux, free radical scavengers and active carbon usage frequencies on the degradation of NB were investigated. In this study, a spray nozzle that could produce 10-micrometer droplets were adopted, a UV lamp that emitted 185nm VUV light was used as the light source and a layer of 0.5cm granular active carbon was laid at the bottom of the experimental apparatus. The results showed that, in the apparatus, when the NB concentration in deionized water was 200mg/L, the nebulization height was 1.3m, O3 flux was 150mg/L, the removal rate of NB reached 95.3%. Supercarbonate acted as a catalyst in the system.