Abstract:The joint is crucial for rock mass engineering,so the inversion of the joint¢s attitude using stress wave is of great engineering significance. Based on the theory of analytic geometry,a formula to calculate traveling time of the reflected wave can be deduced from which direct relationship between a joint¢s true dip direction,true dip angle and the traveling time of measure points can be established. Through complex signal analysis,instantaneous amplitude,phase and frequency of signal can be presented. The signal obtained by the test of jointed rock mass simulation shows that despite the serious interference of Rayleigh wave,the initial arriving moment of the joint reflected wave can still be estimated by instantaneous frequency efficiently. Using the complex signal analysis,the traveling time of several measure points distributing around the source of vibration is gained. And a program based on MATLAB is written to search the center of the isochronous circle,therefore,the inversion of joint¢s attitude can be achieved in the end.