An analysis is made on the past and future trends of wastewater treatment in Beijing. Over the past several decades, great efforts have been made by Beijing to improve the urban wastewater treatment technology, reclaim municipal wastewater, and promote water reclamation and reuse. Until now, the utilization volume of reclaimed water has been increasing continuously. Generally, there are four categories of wastewater treatment plants (WWTPs) in Beijing. And the most mainstream wastewater treatment method in Beijing is aerobic biological process, thereinto the advanced treatment methods of WWTPs, including membrane bioreactor (MBR), biological aerated filter (BAF), and chemical oxidation. However, both the existing conventional and advanced treatment processes mainly aim at the remediation of COD, ammonia nitrogen, total nitrogen, total phosphorus, and other conventional organic pollutants. Micro pollutants such as persistent organic pollutants (POPs) are not considered in the design of WWTPs. The treatment and disposal issues of sludge have become an important agenda item for Beijing’s municipal government. In the future, the priority technologies for wastewater treatment in Beijing should have the features of high efficiency and stability, and lower energy consumption, and operational cost. Suitable small-scale technologies are necessary for rural areas. The existing wastewater treatment facilities must be strengthened and improved to reduce the micro-pollutants in wastewater.