Abstract: The identification and utilization of transformed wave in TOFD parallel scanning was researched based on the theory of ultrasonic wave transformation.The arrival time of shear wave in TOFD parallel scanning was calculated,and the function curve of arrival time of transformed wave against changes of scanning movement was drawn.By means of analysis of parallel scanning image features and in combination with numerical simulation,it was proposed that using the intersections of transformed wave to improve the locating precision of diffraction point.Lastly,the transformed wave in experiment on 48.0 mm thick steel plate was studied,and the method of identification and utilization of transformed wave proposed by the article was validated to have high application value.