Abstract:Aiming at the changing of AE in sandstone, it was analyzed the AE accumulation counts and emission. Analyzing the relationship of AE and rock compression process under loading, it is classified the AE into five stages according the different deformation stages, which are the density stage, the elastic stage, crack stable growth stage, crack unsteady growth stage and the damage stage. Combining rock uniaxial compression results, it is shown that the strain ratio between the AE mutation of critical state and peaking state has a value range 74%and 78%, but the stress ratio has a larger discrete, which has a vaerage value nearly to 73%. In this article, it is discussed the new method to analysis of instability for rock brittle failure based on AE.