The Delphi method is the most common method of technology foresight, which is a significant basis for establishing development strategies and policies of science and technology. This study proposes 45 alternative technologies in the field of environmental engineering science and technology through a literature survey, experts' advice, and discussion meetings. These technologies relate to air pollution prevention and control; water pollution prevention and control; soil pollution prevention and control; solid waste pollution prevention, control, and utilization; ecological protection and restoration; environmental monitoring, early warning, and risk control; resource utilization and cleaner production. Based on results that were obtained according to the Delphi method, this research analyzes the realization time, R&D level, and restriction factors for the key technologies, common technologies, and disruptive technologies that were determined for 2035. This study provides a reference for establishing development strategies and objectives for China’s environmental engineering science and technology over the next 20 years.