Abstract:The strain abnormity magnitude range is 10-9-10-6 from cave temperature’s annual varying, air pressure rising, heavy rainfall, pumping water and unloading of the pressure-bearing aquifer during 2008 to 2013 at Jiujiang seismic station. The mechanisms of cave strain abnormity primarily are the cave material’s temperature effect and extra-stress load-uploading process of the observation hill body. Cave strain observation is sensitive to local stress-stain field, and it may provide the opportunity to capture the strong earthquakes’ precursory abnormity.