Abstract: Based on RS and ground-based survey data, combined with long-term monitoring data of the ecosystem, the water conservation function of Weifang was assessed quantitatively. The results showed that from 2015 to 2020, there was significant spatial heterogeneity in the distribution of water conservation in the region.Water conservation in Weifang increased first and then declined from 2015 to 2020, with the highest levels of water conservation occurring in the forest ecosystems in the southwest and wetland ecosystems in the north.During 2015—2019, total water conservation in Weifang has been on the rise, and the ability of soil to conserve water and regulate surface runoff has been gradually enhanced. However, in 2020, due to climate and other factors, total water conservation in Weifang decreased considerably, which was basically back to 2015 level.