Based on laboratory AE(acoustic emission) tests of rock,the relationship between stress and AE rate and the distribution behavior of AE temporal sequence in the process of failure and deformation have been studied.The related law of distribution characteristics of AE temporal sequence and the evolvement of rock crack is presented.The monitoring result on site shows that AE signal from rock crack evolvement is stochastic and non-periodic,varies with geologic environment etc.There are sudden changes of AE temporal sequence parameters of rock,and the changes are suddenly from small to larger or suddenly fall after continuous increasing,these are signs that rock approaches to damage,can be regarded as basis to forecast and predict fracture of rock mass.