The removal rate of total petroleum hydrocarbons (TPH) can be improved by stepwise addition of H₂O₂, and the 900 mmol/L H₂O₂ was divided into 3 times for stepwise Fenton oxidation to remediate the soil polluted by long chain oil in this study. Experiment was conducted under the four catalysis systems, i.e., Fe²⁺, solid iron, Fe²⁺+ hydroxylamine hydrochloride, solid iron + hydroxylamine hydrochloride. It was found that ?OH intensities were facilitated significantly in the last two reactions when hydroxylamine hydrochloride was added to Fe²⁺ and solid iron systems, which was 3–4 times of the system without hydroxylamine hydrochloride. The oxidation of TPH and long chain hydrocarbon were also greatly increased. Hydroxylamine hydrochloride could overcome the shortcomings of significant reduction of ?OH intensity than the first stage and the significant decreases of oxidation of TPH and long chain hydrocarbons which are attributed to the lack of Fe²⁺, facilitated significantly ?OH production in second and third stages, thus, greatly improved the removal efficiencies of TPH and long chain hydrocarbon similar to the first stage and could be maintained at a higher level. This study could provide certain theoretical bases for the urgent need for short-term soil remediation.