Nitrobenzene Compounds, featured with weak mutagenicity, chemical stability, were difficult to be purified by traditional degradation method. The paper comparatively analyzed several factors involved in the nitrobenzene wastewater degradation by cavitating water jets assisted by Fenton. The removal ratio of nitrobenzene, whose concentration was 50mg/L, reaches 95.06% when the Fe2+ concentration was 40mg/L, the pH value, 5.0, the hydrogen peroxide concentration, 150mg/L, the confining pressure, 0.5MPa, and the jetting pressure, 10Mpa. The degradation mechanism, shown by high performance liquid chromatography (HPLC), is that the cavitating water jet impelled the Fenton to release more HO• and enhanced the catalytic capacity of Fe2+, then the nitrobenzene was degraded or oxidized totally, or was graded into small organic molecules such as chain hydrocarbon and organic acids etc. Besides, the intermediate products, including Benzoquinone, 4-Nitrophenol, 2-Nitrophenol and Hydroquinone, were also shown by HPLC.