Abstract: Because it is a nonlinear dynamic process,chaos characteristic of rock burst is analyzed systematically and thoroughly on microseism time series to laying a foundation for chaotic prediction.chaos characteristic appearance of rock burst is introduced in this paper.In MATLABR2009b environment,taking the time series of microseism accumulative total energy as an example,aperiodicity is confirmed with power spectrum method;the time series is distinguished from the noise signal by the principal components analysis;chaos characteristic of the system is determined by its maximum lyapunov exponent which is greater than zero;correlation dimension calculated describes its chaotic degree.