In ultrasonic NDE flaw signals may be contaminated by noise, even inundated. Under such circumstances, it is difficult to distinguish the flaw signal from the background noise directly. In this paper, a new ultrasonic NDE technique is presented using the phase characteristics of the noise free flaw echoes by the Morlet WT. These phase characteristics are derived using a geometrical approach. The results presented here show the potential of the proposed technique for detecting flaws in complex environments. Further work is planned to research the determination method of the entropy threshold I_p, and to compare the technique with the other ultrasonic signal processing techniques to further assess the capabilities of the technique.