Abstract: The wastewater generated by the sudden environmental pollution accidents in the chemical parks has the characteristics of high concentration and toxicity, complex pollutant composition, and difficulty in emergency treatment, which is seriously harmful to the ecological environment and has a great social impact. In response to the needs of emergency treatment of wastewater from the explosion pit of Xiangshui Chemical Industry Park explosion accident, research on wastewater quality analysis, treatment process screening, bench-scale test, and project implementation effect was carried out. The bench-scale test showed that by the pretreatment of activated carbon enhanced activated sludge (AC-AS), the pollutant concentration of the explosion pit wastewater was greatly reduced, the removal efficiency of total organic carbon and ammonia nitrogen reached 96.9% and 65.7%, respectively, and the pretreated effluent met the influent requirements of the follow-up Chenjiagang Wastewater Treatment Plant (WTP). The project operation showed that after the pretreatment of AC-AS, and the treatment of WTP, all indicators of the effluent (COD, ammonia nitrogen and other pollutants) met the discharge standards of Discharge Standard of Main Water Pollutants for Chemical Industry of Jiangsu Province (DB 32/939-2006) and Emission Standard of Pollutants for Petrochemical Industry (GB 31571-2015). The emergency treatment project reduced chemical oxygen demand by 33319.6 kg, ammonia nitrogen by 209.4 kg, and aniline by 6.2 kg. After the wastewater was treated up to the discharge standard by Chenjiagang WTP, the water quality of the downstream receiving water body kept normal and the water environment was not significantly adversely affected. This wastewater treatment case showed that AC-AS had a good treatment effect on this kind of accidental wastewater.