Abstract: When using transversal wave to circumferentially survey surface, the circumferential flaw localization, is one problem that the ultrasonic wave testing meets frequently. There exist many localization methods in this aspect, with each having its own advantage and disadvantage respectively. This article, by using the transversal wave circumferential testing, analyzed flaw localization formula for the outer and internal annulus first wave and second wave. It expounded that the diagram of curves plan method and the step, draw up figure through the CAD charting method(also to be possible on coordinate paper manual charting) to carry on the localization to the flaw. Finally, it summarized matters needed attention and the applicable scope on the use of the related curves and figures.