Abstract: Observation data of vertical pendulum inclinometer in the NS direction accelerated incline to the south from Oct.2007 and lasted for 2 years, while it accelerated incline to the north since Nov.2009.At the same time, the EW direction accelerated incline to the east.In this paper, the possible disturbance sources are analyzed as well as the relationship between temperature and Yuqiao reservoir capacity based on the annual change of the data combining with data of water pipe slant instrument in the same cave.The result indicates that change since Nov.2009 was true and contained seismic precursor information.