Beijing and Tianjin are two very big cities with abundant low-temperature geothermal in China,using it mostly for space heating,bathing,health spas and recreation,fish farming,greenhouses and domestic hot water etc.With the improving living conditions of the citizens,the need for geothermal water is ever increasing in the cities.Large-scale abstraction of geothermal water caused a rapid declining of the water level of the geothermal wells in both Beijing and Tianjin,and how to ensure the sustainability of geothermal utilization has been taken as the most important task.Apart from the limitation of geothermal water production,reinjection is also taken as an important aspect of geothermal management.Reinjection has been widely applied in the management of geothermal resources,and is becoming a kind of routine in a lot of geothermal fields.In China,reinjection tests started in 1974 in the City of Beijing.But reinjection of used geothermal water from heating systems in scale was started in the City of Tianjin in the 1990s.Since 2000,reinjection has been taken as a more and more important aspect of geothermal resources management in the two cities.At present,a number of reinjection projects have been in operation in Beijing and Tianjin.As a result,the water level declining of the geothermal wells has been greatly mitigated.In Xiaotangshan geothermal field of Beijing,the water level has even stopped declining since 2006,owing to the reinjection and controlling of the production of geothermal water.The reinjection history in both Beijing and Tianjin will be summarized,and the experiences and problems of reinjection,including the distance between the production and reinjection wells,tracer test and monitoring of geothermal fields with reinjection will be discussed.