Abstract:The treatment and remediation of pollution at contaminated mega-sites poses a significant challenge in the environmental science both domestically and internationally. Contaminated mega-sites are characterized by their widespread impact, multiple types of pollutants, and significant ecological and environmental threats. The environmental behavior cognition and efficient remediation at contaminated mega-sites face enormous challenges, among which key technological issues such as the formation mechanism of soil and groundwater pollution, accurate identification of pollution sources, and intelligent decision-making optimization urgently need to be solved. In China, contaminated mega-sites are concentrated in economically developed regions such as Beijing-Tianjin-Hebei, the Yangtze River Economic Belt, and the Pearl River Delta, and involve industries like chemical manufacturing, oil and other fuel processing industries, and ferrous metal smelting. Taking into account the national context, this study proposes a three step model for the remediation and treatment of contaminated mega-sites (TSRTCM), focusing on addressing the problems from three steps: investigation and scientific cognition, decision-making and screening techniques, and engineering implementation and monitoring evaluation. The environmental remediation of contaminated mega-sites can effectively support the battle against pollution prevention and contribute to the green development of regional economy and society.