[Objective] The dynamics of water-related ecosystem services and its influences by south-to-north water diversion project were analyzed

in order to protect water resources and ecosystem balance of Miyun Reservoir. [Methods] The methods of market value

alternating engineering

alternative cost

carbon trading

willingness to pay

proportion apportionment and benefit transfer were used to evaluate the water-related ecosystem services of water resources supply

aquatic product provision

flood regulation and reservation

air humidity improvement

summer heat amelioration

water purification

water conservation

CO2 sequestration

O2 release

biodiversity protection

tourism and leisure and scientific research and education of Miyun Reservoir. [Results] The water-related ecosystem service values of Miyun Reservoir ranged from 70.996 to 100.360 billion during 2008—2019

which fluctuated slightly at first and then increased. As for components of water-related ecosystem services

the value of supporting services

especially biodiversity protection

played a dominant role (64%~80%). The value of regulating services was in the secondary position (18%~33%)

which was mainly manifested in water conservation

humidity improvement

summer heat amelioration and flood regulation and reservation. The value of provisioning services and cultural services together accounted for less than 5%. Moreover

the south-to-north water diversion project significantly increased the values of air humidity improvement

summer heat amelioration

water conservation

water purification

tourism and leisure

scientific research and education and total ecosystem services (p<0.01)

while significantly decreased the value of flood regulation and reservation (p<0.01). [Conclusion] The water ecological service function of Miyun Reservoir is affected not only by natural factors such as climate

but also by human factors such as south to north water diversion project and traffic convenience. The monitoring of water volume and quality and the development of cultural and ecological potential of Miyun Reservoir should be strengthened

so as to guarantee the security and reliability of drinking water reserves for Beijing City.