Abstract: A set of new water temperature observation instrument was placed in New 30 well in Xinjiang. When the old and new instruments observed at different depths simultaneously, the record curves are different, so the depth and place where the instruments were installed influence the observation result obviously. Through analyzing the observation data of water temperature test instrument, we found that when the instrument was installed at depth of 180 to 185 m, the water temperature daily variation is regular and changes synchronously with the water level in the same well, and there is tide change. At last, the daily variation shape and earthquake reflecting sensitivity at different depth are analyzed, and the rational instrument installing depth has been preliminarily determined to be 180 m.

Key words: Water temperature at different depths, Observation test, New 30 well