Based on the water temperature observation data of the national underground fluid observation network,this paper analyzed the characteristics of the water temperature coseismic response caused by the Sichuan Luding M_S6.8 earthquake on September 5,2022,and discussed the mechanism of the water temperature coseismic response related with the coseismic static strain field. The results show that the water temperature coseismic observation points of the Luding M_S6.8 earthquake are mainly distributed in the Longmenshan fault belt and the central south of the rhombus block in Sichuan and Yunnan Provinces. In the range of epicentral distance Δ≤500km,coseismic responses are dominant by patterns of decline-recovery and rise. The number of water temperature coseismic factors and their ratio gradually decrease with the increase of the earthquake epicentral distance. The coseismic response amplitude of water temperature is significantly related to the epicentral distance and seismic energy density,showing exponential decay with the increase of epicentral distance while increasing exponentially with the increase of seismic energy density. The duration of the water temperature coseismic response is mainly within one day and decreases exponentially with the increase of epicentral distance.