Abstract：The main states of borehole strain measurement, a variety of earthquake cases were analyzed. The results show that the borehole strain anomalies before earthquakes in most cases were located in the region far from the source, while near the source region significant precursor were rarely observed. This fact, on the one hand, may reflect the lack of the borehole strain sites and uneven distribution of them; the other hand, may reflect the mechanical properties of the focal region, that in a focal region before the rupture there are high strain accumulation and small deformation.
