Abstract: Wastewater treatment plants that are recognized as one of the main sources of greenhouse gas (GHG) are undergoing an innovative transformation from "standard emission" to sustainable sewage treatment. Carbon neutrality operation has become the core content of future wastewater treatment. The characteristic of traditional activated sludge processes is the transform of pollutants and energy. The traditional wastewater treatment process adopts the way of "energy dissipation" and "pollution transfer", which consumes lots of energy and emits a large number of greenhouse gases such as CO₂ and N₂O. To reduce the greenhouse gas emissions from wastewater treatment plants effectively, the current technical measures to achieve carbon neutrality operation from both macro and micro perspectives were analyzed and the use of domestic and foreign sewage treatment plants to increase energy sources and reduce expenditures were introduced in this paper. The successful experiences that domestic and foreign wastewater treatment plants to increase energy utilization and reduce energy consumption were introduced, which provided a significant reference for reducing the carbon emissions of wastewater treatment plants, gradually realizing the low-carbon operation of wastewater treatment plants and steadily approaching the ultimate goal of "carbon neutrality".