Abstract：In millisecond blasting，the designed or selected delay time is always different from the real one due to the delay errors of ordinary short delay detonators. The problem influences both the effect and successful implementation of blast. It is significant to identify real time of delay in millisecond blasting. The time-energy density analysis based on the wavelet transform has the character of making the abrupt change of signal energy prominent and can effectually identify the blasting moment of short-delay detonators. Then the real time of delay can be ascertained by analyzing the energy distribution of the monitoring signals in millisecond blasting，and the problem mentioned above can be solved successfully. The effectiveness of the proposed method is verified with time-energy density analysis of vibration signals of millisecond blasting in an underground engineering. The method can be also applied to analyze the attenuation laws of energy for blasting vibration signals during the propagation，blasting mechanism and blasting seismic effects in its entirety.
