On December 21,2000,Ningbo seismic station ZK03 well started the test of the water temperature（a ninth ＂Five-year Plan＂ water temperature project）.Ten years later on April 2,2010,in the same well at the same depth a new set of water temperature instrument was installed to start the parallel observation（the tenth ＂Five-year Plan＂ water temperature）.The results show that the absolute precisions of the water temperature measurements are basically the same at the installments of the instruments,which means that the well water temperature rising trend in ten years is not the result of the temperature change of the well hole internal waters,but that of the instrument systemic changes,namely the instrument drifts,and has not obvious influence on earthquake precursory observations.Through nearly nine months of parallel observation,the two sets of instruments are generally consistent in the measure value trend.When interfered with lightning or electrical impulses,they showed different water temperature measurements,and this may have something to do with the systematic characteristics of each instrument.In spite of the interferences of the water temperature measurements of the ninth ＂Five-year Plan＂ water thermometer by the tenth ＂Five-year Plan＂ one,the sensitivity of the former is still high although it has worked continuously for more than ten years.[著者文摘]