Abstract: Using the water temperature observations sampled in minute rate at the Ning-Jin-Ji Well 22 station, data features, such as daily average, short time average, and their corresponding ranges and standard deviations are calculated , and the calculated features are analyzed. The results suggest that: (1) Performance of observation instruments can affect final measurements; (2) Performance in the real observation environment may differ from that in the laboratory, resulting in incompetence with the requirements of the real observation environment; (3) The different performances of each instrument can be obtained through the calculation and analysis of a large number of observations, therefore observations can be used to infer instrument performance differences. The data analysis cases shown in this paper provide a research idea that performance of the instrument can be analyzed by using a large amount of data.