Abstract: Study on deep aquifer's water level and water temperature dynamics is mainly by the describing of the morphologic variation and the analysis to annually dynamic character at present.Based on the relation between water level and temperature,the stability of the linear correlation coefficient r and the variation of regression coefficient b with time are studied.We find the r and b values are stable during the period that earthquake activity is quiet,but vary greatly when earthquake is active.The variations of r and b value before and after Datong M_s6.1 earthquake (Oct.19,1989) and Zhangbei M_s6.2 earthquake (Jan.10,1998) are discussed.The results show we can get more information through comparison than just to discuss them respectively.From the analysis to the relation of underground water level with water temperature we can see that the water level's variation is the response of the aquifer system's thermal balance.Thus to study the underground water level's dynamics we must study the temperature's variation simultaneously.