It were recorded that a large number of co-seismic responses of well water level and temperature in Chinese mainland caused by the Nepal MS
8.1 earthquake. There is good correlation between well water level and water temperature for 51 observation wells, which appears as water level rise to water temperature rise, water level drop to water temperature drop or water level oscillation to water temperature rise/drop (most of the co-seismic water tempe-ratures drop). The good correlation is resulted from the groundwater dynamics. As for three observation wells, the change in water level is in the opposite direction to the change in water temperature, which is the post-seismic effect. Meanwhile, one observation well has only water temperature co-seismic change but no water level change, which may have great relation to the borehole condition, water temperature gradient, sensor position and water level depth. The results also show that there is complex relationship between the initial time and amplitude of groundwater level change and those of groundwater temperature change, which is affected by borehole condition and temperature gradient.