During the Tohoku M9.0 great earthquake of March 11th, 2011, the digital observation data on underground fluids in the Gansu area showed different degrees of co-seismic response. In this study, we analyzed the co-seismic change characteristics and response ability of the digital water levels and water temperature in the Gansu area during the earthquake. It was found that the co-seismic response of the water level had two main patterns:oscillation and mutation. The water level of most wells returned to the initial state a short time after the earthquake. The recorded water temperature data showed a lower response capacity than the water level data. Only one of the measurement instruments recorded the co-seismic response of the water temperature, but this was just a short-term fluctuation and it easily recovered.