This research mainly used the electrostatic interaction and self-assembly of surfactant to induce the formation of CTAB-PdNPs aggregation. The results showed that the electrostatic interaction between the cationic surfactant and anionic Pd precursor can shield the electrostatic repulsion between the hydrophilic groups of CTA+. It drives the formation of CTAB-PdNPs aggregation on the molecular level. This study chose p-CNB as target pollutant and its catalytic reduction as probe, showing that CTAB-PdNPs have high catalytic activity and dehalogenation ability which can convert p-CNB into aniline in 90 minutes. Besides, this study further investigated the effect of Pd dosages，CTAB concentration, initial pH and NaBH4 dosages on the catalytic reduction. The optimum conditions were Pd dosage value of 0.125 mmol/L，CTAB concentration value of 1.0 mmol/L，initial pH value of 5 and NaBH4 dosage value of 15 mmol/L. The dechlorination efficiency of p-CNB can reach up to 81.9% after eight times recycle tests，which proves the aggregation has an outstanding catalytic stability. Above all，this study not only reports a new method of synthesizing PdNPs assembly with special regular shapes，but also provides a feasible technology for the removal of micro-pollutants in the environment.